diff --git a/index.html b/index.html
index 373bb7b0..7a1f782c 100644
--- a/index.html
+++ b/index.html
@@ -1775,6 +1775,18 @@
               </td>
             </tr>
 
+            <tr data-tip="Set what Generator should do on load">
+              <td></td>
+              <td>Onload behavior</td>
+              <td>
+                <select id="onloadBehavior" data-stored="onloadBehavior">
+                  <option value="random" selected>Generate random map</option>
+                  <option value="lastSaved">Open last saved map</option>
+                </select>
+              </td>
+              <td></td>
+            </tr>
+
             <tr data-tip="Select speech synthesis voice to pronounce generated names">
               <td></td>
               <td>Speaker voice</td>
@@ -2329,8 +2341,8 @@
         <div id="sticked">
           <button id="newMapButton" data-tip="Generate a new map based on options" data-shortcut="F2">New Map</button>
           <button id="exportButton" data-tip="Select format to download image or export map data">Export</button>
-          <button id="saveButton" data-tip="Save fully-functional map in .map format">Save</button>
-          <button id="loadButton" data-tip="Load fully-functional map in .map format">Load</button>
+          <button id="saveButton" data-tip="Save fully-functional map in .gz format">Save</button>
+          <button id="loadButton" data-tip="Load fully-functional map (.gz or .map formats)">Load</button>
           <button id="zoomReset" data-tip="Reset map zoom" data-shortcut="0 (zero)">Reset Zoom</button>
         </div>
       </div>
@@ -5884,37 +5896,42 @@
       <div id="saveMapData" style="display: none" class="dialog">
         <div style="margin-top: 0.3em">
           <strong>Save map to</strong>
-          <button onclick="dowloadMap()" data-tip="Download .map file to your local disk" data-shortcut="Ctrl + S">
+          <button onclick="saveMap('machine')" data-tip="Download map file to your local disk" data-shortcut="Ctrl + S">
             machine
           </button>
-          <button onclick="saveToDropbox()" data-tip="Save .map file to your Dropbox" data-shortcut="Ctrl + C">
+          <button onclick="saveMap('dropbox')" data-tip="Save map file to your Dropbox" data-shortcut="Ctrl + C">
             dropbox
           </button>
-          <button
-            onclick="quickSave()"
-            data-tip="Save the project to browser storage. It will overwrite the latest autosave"
-            data-shortcut="F6"
-          >
+          <button onclick="saveMap('storage')" data-tip="Save the project to browser storage only" data-shortcut="F6">
             browser
           </button>
         </div>
         <p>
-          Maps are saved in <i>.map</i> format, that can be loaded back via the <i>Load</i> in menu. There is no way to
-          restore the progress if file is lost. Please keep old <i>.map</i> files on your machine or cloud storage as
-          backups.
+          Maps are saved in <i>.gz</i> format, that can be loaded back via the <i>Load</i> in menu. There is no way to
+          restore the progress if file is lost. Please keep old save files on your machine or cloud storage as backups.
         </p>
       </div>
 
       <div id="loadMapData" style="display: none" class="dialog">
         <div>
           <strong>Load map from</strong>
-          <button onclick="mapToLoad.click()" data-tip="Load .map file from your local disk">machine</button>
-          <button onclick="loadURL()" data-tip="Load .map file from URL (server should allow CORS)">URL</button>
+          <button onclick="mapToLoad.click()" data-tip="Load map file (.gz or .map) from your local disk">
+            machine
+          </button>
+          <button
+            onclick="loadURL()"
+            data-tip="Load map file (.gz or .map) file from URL. Note that the server should allow CORS"
+          >
+            URL
+          </button>
           <button onclick="quickLoad()" data-tip="Load map from browser storage (if saved before)">storage</button>
         </div>
+
+        <p>Click on <i>storage</i> to open the last saved map.</p>
+
         <div id="loadFromDropbox">
           <p style="margin-bottom: 0.3em">
-            From your Dropbox account
+            Or load from your Dropbox account
             <button
               id="dropboxConnectButton"
               onclick="connectToDropbox()"
@@ -5926,7 +5943,7 @@
 
           <select id="loadFromDropboxSelect" style="width: 22em"></select>
           <div id="loadFromDropboxButtons" style="margin-bottom: 0.6em">
-            <button onclick="loadFromDropbox()" data-tip="Load .map file from your Dropbox">Load</button>
+            <button onclick="loadFromDropbox()" data-tip="Load map file (.gz or .map) from your Dropbox">Load</button>
             <button
               onclick="createSharableDropboxLink()"
               data-tip="Select file and create a link to share with your friends"
@@ -5995,7 +6012,7 @@
       <div id="resampleDialog" style="display: none" class="dialog">
         <div style="width: 34em; max-width: 80vw; font-weight: bold; padding: 6px">
           This operation is destructive and irreversible. It will create a completely new map based on the current one.
-          Don't forget to save the current project as a .map file first!
+          Don't forget to save the current project to your machine first!
         </div>
 
         <div
@@ -6116,10 +6133,10 @@
       data-main="Сlick the arrow button for options. Zoom in to see the map in details"
     ></div>
 
-    <div id="mapOverlay" style="display: none">Drop a .map file to open</div>
+    <div id="mapOverlay" style="display: none">Drop a map file to open</div>
 
     <div id="fileInputs" style="display: none">
-      <input type="file" accept=".map" id="mapToLoad" />
+      <input type="file" accept=".map,.gz" id="mapToLoad" />
       <input type="file" accept=".txt,.csv" id="burgsListToLoad" />
       <input type="file" accept=".txt" id="legendsToLoad" />
       <input type="file" accept="image/*" id="imageToLoad" />
@@ -7930,7 +7947,7 @@
     <script src="utils/graphUtils.js?v=1.90.01"></script>
     <script src="utils/nodeUtils.js"></script>
     <script src="utils/numberUtils.js?v=1.89.08"></script>
-    <script src="utils/polyfills.js"></script>
+    <script src="utils/polyfills.js?v=1.93.00"></script>
     <script src="utils/probabilityUtils.js?v=1.88.00"></script>
     <script src="utils/stringUtils.js"></script>
     <script src="utils/languageUtils.js"></script>
@@ -7963,15 +7980,15 @@
     <script src="modules/ui/stylePresets.js?v=1.89.11"></script>
 
     <script src="modules/ui/general.js?v=1.87.03"></script>
-    <script src="modules/ui/options.js?v=1.91.00"></script>
-    <script src="main.js?v=1.92.00"></script>
+    <script src="modules/ui/options.js?v=1.93.00"></script>
+    <script src="main.js?v=1.93.00"></script>
 
     <script defer src="modules/relief-icons.js"></script>
     <script defer src="modules/ui/style.js"></script>
     <script defer src="modules/ui/editors.js?v=1.92.00"></script>
     <script defer src="modules/ui/tools.js?v=1.92.00"></script>
     <script defer src="modules/ui/world-configurator.js?v=1.91.05"></script>
-    <script defer src="modules/ui/heightmap-editor.js?v=1.92.00"></script>
+    <script defer src="modules/ui/heightmap-editor.js?v=1.93.00"></script>
     <script defer src="modules/ui/provinces-editor.js?v=1.92.00"></script>
     <script defer src="modules/ui/biomes-editor.js?v=1.91.05"></script>
     <script defer src="modules/ui/namesbase-editor.js?v=1.89.26"></script>
@@ -8001,13 +8018,12 @@
     <script defer src="modules/ui/markers-editor.js"></script>
     <script defer src="modules/ui/3d.js?v=1.89.36"></script>
     <script defer src="modules/ui/submap.js?v=1.92.00"></script>
-    <script defer src="modules/ui/hotkeys.js?v=1.88.00"></script>
+    <script defer src="modules/ui/hotkeys.js?v=1.93.00"></script>
     <script defer src="modules/coa-renderer.js?v=1.91.00"></script>
     <script defer src="libs/rgbquant.min.js"></script>
     <script defer src="libs/jquery.ui.touch-punch.min.js"></script>
-
-    <script defer src="modules/io/save.js?v=1.91.04"></script>
-    <script defer src="modules/io/load.js?v=1.92.05"></script>
+    <script defer src="modules/io/save.js?v=1.93.00"></script>
+    <script defer src="modules/io/load.js?v=1.93.00"></script>
     <script defer src="modules/io/cloud.js"></script>
     <script defer src="modules/io/export.js?v=1.89.36"></script>
     <script defer src="modules/io/formats.js"></script>
diff --git a/main.js b/main.js
index 4c40de43..ba7d1ee5 100644
--- a/main.js
+++ b/main.js
@@ -270,7 +270,7 @@ async function checkLoadParameters() {
   const url = new URL(window.location.href);
   const params = url.searchParams;
 
-  // of there is a valid maplink, try to load .map file from URL
+  // of there is a valid maplink, try to load .gz/.map file from URL
   if (params.get("maplink")) {
     WARN && console.warn("Load map from URL");
     const maplink = params.get("maplink");
@@ -292,17 +292,20 @@ async function checkLoadParameters() {
   }
 
   // check if there is a map saved to indexedDB
-  try {
-    const blob = await ldb.get("lastMap");
-    if (blob) {
-      WARN && console.warn("Loading last stored map");
-      uploadMap(blob);
-      return;
+  if (byId("onloadBehavior").value === "lastSaved") {
+    try {
+      const blob = await ldb.get("lastMap");
+      if (blob) {
+        WARN && console.warn("Loading last stored map");
+        uploadMap(blob);
+        return;
+      }
+    } catch (error) {
+      ERROR && console.error(error);
     }
-  } catch (error) {
-    console.error(error);
   }
 
+  // else generate random map
   WARN && console.warn("Generate random map");
   generateMapOnLoad();
 }
@@ -574,9 +577,10 @@ void (function addDragToUpload() {
     overlay.style.display = "none";
     if (e.dataTransfer.items == null || e.dataTransfer.items.length !== 1) return; // no files or more than one
     const file = e.dataTransfer.items[0].getAsFile();
-    if (file.name.indexOf(".map") == -1) {
-      // not a .map file
-      alertMessage.innerHTML = "Please upload a <b>.map</b> file you have previously downloaded";
+
+    if (!file.name.endsWith(".map") && !file.name.endsWith(".gz")) {
+      alertMessage.innerHTML =
+        "Please upload a map file (<i>.gz</i> or <i>.map</i> formats) you have previously downloaded";
       $("#alert").dialog({
         resizable: false,
         title: "Invalid file format",
@@ -596,7 +600,7 @@ void (function addDragToUpload() {
     if (closeDialogs) closeDialogs();
     uploadMap(file, () => {
       overlay.style.display = "none";
-      overlay.innerHTML = "Drop a .map file to open";
+      overlay.innerHTML = "Drop a map file to open";
     });
   });
 })();
diff --git a/modules/dynamic/auto-update.js b/modules/dynamic/auto-update.js
index 44f84283..b88e7d43 100644
--- a/modules/dynamic/auto-update.js
+++ b/modules/dynamic/auto-update.js
@@ -1,6 +1,6 @@
 "use strict";
 
-// update old .map version to the current one
+// update old map file to the current version
 export function resolveVersionConflicts(version) {
   if (version < 1) {
     // v1.0 added a new religions layer
diff --git a/modules/io/load.js b/modules/io/load.js
index 33d7eea4..00e46bc9 100644
--- a/modules/io/load.js
+++ b/modules/io/load.js
@@ -1,6 +1,5 @@
 "use strict";
-// Functions to load and parse .map files
-
+// Functions to load and parse .gz/.map files
 async function quickLoad() {
   const blob = await ldb.get("lastMap");
   if (blob) loadMapPrompt(blob);
@@ -112,11 +111,11 @@ function uploadMap(file, callback) {
   const currentVersion = parseFloat(version);
 
   const fileReader = new FileReader();
-  fileReader.onload = function (fileLoadedEvent) {
+  fileReader.onloadend = async function (fileLoadedEvent) {
     if (callback) callback();
     document.getElementById("coas").innerHTML = ""; // remove auto-generated emblems
     const result = fileLoadedEvent.target.result;
-    const [mapData, mapVersion] = parseLoadedResult(result);
+    const [mapData, mapVersion] = await parseLoadedResult(result);
 
     const isInvalid = !mapData || isNaN(mapVersion) || mapData.length < 26 || !mapData[5];
     const isUpdated = mapVersion === currentVersion;
@@ -131,18 +130,40 @@ function uploadMap(file, callback) {
     if (isOutdated) return showUploadMessage("outdated", mapData, mapVersion);
   };
 
-  fileReader.readAsText(file, "UTF-8");
+  fileReader.readAsArrayBuffer(file);
 }
 
-function parseLoadedResult(result) {
+async function uncompress(compressedData) {
   try {
+    const uncompressedStream = new Blob([compressedData]).stream().pipeThrough(new DecompressionStream("gzip"));
+
+    let uncompressedData = [];
+    for await (const chunk of uncompressedStream) {
+      uncompressedData = uncompressedData.concat(Array.from(chunk));
+    }
+
+    return new Uint8Array(uncompressedData);
+  } catch (error) {
+    ERROR && console.error(error);
+    return null;
+  }
+}
+
+async function parseLoadedResult(result) {
+  try {
+    const resultAsString = new TextDecoder().decode(result);
     // data can be in FMG internal format or base64 encoded
-    const isDelimited = result.substr(0, 10).includes("|");
-    const decoded = isDelimited ? result : decodeURIComponent(atob(result));
+    const isDelimited = resultAsString.substring(0, 10).includes("|");
+    const decoded = isDelimited ? resultAsString : decodeURIComponent(atob(resultAsString));
+
     const mapData = decoded.split("\r\n");
     const mapVersion = parseFloat(mapData[0].split("|")[0] || mapData[0]);
     return [mapData, mapVersion];
   } catch (error) {
+    // map file can be compressed with gzip
+    const uncompressedData = await uncompress(result);
+    if (uncompressedData) return parseLoadedResult(uncompressedData);
+
     ERROR && console.error(error);
     return [null, null];
   }
@@ -153,7 +174,7 @@ function showUploadMessage(type, mapData, mapVersion) {
   let message, title, canBeLoaded;
 
   if (type === "invalid") {
-    message = `The file does not look like a valid <i>.map</i> file.<br>Please check the data format`;
+    message = `The file does not look like a valid save file.<br>Please check the data format`;
     title = "Invalid file";
     canBeLoaded = false;
   } else if (type === "ancient") {
@@ -165,7 +186,7 @@ function showUploadMessage(type, mapData, mapVersion) {
     title = "Newer file";
     canBeLoaded = false;
   } else if (type === "outdated") {
-    message = `The map version (${mapVersion}) does not match the Generator version (${version}).<br>Click OK to get map <b>auto-updated</b>.<br>In case of issues please keep using an ${archive} of the Generator`;
+    message = `The map version (${mapVersion}) does not match the Generator version (${version}).<br>That is fine, click OK to the get map <b style="color: #005000">auto-updated</b>.<br>In case of issues please keep using an ${archive} of the Generator`;
     title = "Outdated file";
     canBeLoaded = true;
   }
@@ -435,7 +456,7 @@ async function parseLoadedData(data) {
     {
       // dynamically import and run auto-udpdate script
       const versionNumber = parseFloat(params[0]);
-      const {resolveVersionConflicts} = await import("../dynamic/auto-update.js?v=1.92.05");
+      const {resolveVersionConflicts} = await import("../dynamic/auto-update.js?v=1.93.00");
       resolveVersionConflicts(versionNumber);
     }
 
diff --git a/modules/io/save.js b/modules/io/save.js
index 97cf7c09..42fcb355 100644
--- a/modules/io/save.js
+++ b/modules/io/save.js
@@ -1,8 +1,43 @@
 "use strict";
-// functions to save project as .map file
 
-// prepare map data for saving
-function getMapData() {
+// functions to save the project to a file
+async function saveMap(method) {
+  if (customization) return tip("Map cannot be saved in EDIT mode, please complete the edit and retry", false, "error");
+  closeDialogs("#alert");
+
+  try {
+    const compressedMapData = await compressData(prepareMapData());
+    const filename = getFileName() + ".gz";
+
+    saveToStorage(compressedMapData, method === "storage"); // any method saves to indexedDB
+    if (method === "machine") saveToMachine(compressedMapData, filename);
+    if (method === "dropbox") saveToDropbox(compressedMapData, filename);
+  } catch (error) {
+    ERROR && console.error(error);
+    alertMessage.innerHTML = /* html */ `An error is occured on map saving. If the issue persists, please copy the message below and report it on ${link(
+      "https://github.com/Azgaar/Fantasy-Map-Generator/issues",
+      "GitHub"
+    )}. <p id="errorBox">${parseError(error)}</p>`;
+
+    $("#alert").dialog({
+      resizable: false,
+      title: "Saving error",
+      width: "28em",
+      buttons: {
+        Retry: function () {
+          $(this).dialog("close");
+          saveMap(method);
+        },
+        Close: function () {
+          $(this).dialog("close");
+        }
+      },
+      position: {my: "center", at: "center", of: "svg"}
+    });
+  }
+}
+
+function prepareMapData() {
   const date = new Date();
   const dateString = date.getFullYear() + "-" + (date.getMonth() + 1) + "-" + date.getDate();
   const license = "File can be loaded in azgaar.github.io/Fantasy-Map-Generator";
@@ -117,36 +152,30 @@ function getMapData() {
   return mapData;
 }
 
-// Download .map file
-function dowloadMap() {
-  if (customization)
-    return tip("Map cannot be saved when edit mode is active, please exit the mode and retry", false, "error");
-  closeDialogs("#alert");
+// save map file to indexedDB
+async function saveToStorage(compressedMapData, showTip = false) {
+  const blob = new Blob([compressedMapData], {type: "text/plain"});
+  await ldb.set("lastMap", blob);
+  showTip && tip("Map is saved to the browser storage", false, "success");
+}
 
-  const mapData = getMapData();
-  const blob = new Blob([mapData], {type: "text/plain"});
+// download .gz file
+function saveToMachine(compressedMapData, filename) {
+  const blob = new Blob([compressedMapData], {type: "text/plain"});
   const URL = window.URL.createObjectURL(blob);
+
   const link = document.createElement("a");
-  link.download = getFileName() + ".map";
+  link.download = filename;
   link.href = URL;
   link.click();
-  tip(`${link.download} is saved. Open "Downloads" screen (CTRL + J) to check`, true, "success", 7000);
+
+  tip('Map is saved to the "Downloads" folder (CTRL + J to open)', true, "success", 8000);
   window.URL.revokeObjectURL(URL);
 }
 
-async function saveToDropbox() {
-  if (customization)
-    return tip("Map cannot be saved when edit mode is active, please exit the mode and retry", false, "error");
-  closeDialogs("#alert");
-  const mapData = getMapData();
-  const filename = getFileName() + ".map";
-  try {
-    await Cloud.providers.dropbox.save(filename, mapData);
-    tip("Map is saved to your Dropbox", true, "success", 8000);
-  } catch (msg) {
-    ERROR && console.error(msg);
-    tip("Cannot save .map to your Dropbox", true, "error", 8000);
-  }
+async function saveToDropbox(compressedMapData, filename) {
+  await Cloud.providers.dropbox.save(filename, compressedMapData);
+  tip("Map is saved to your Dropbox", true, "success", 8000);
 }
 
 async function initiateAutosave() {
@@ -161,38 +190,43 @@ async function initiateAutosave() {
     if (diffInMinutes < timeoutMinutes) return;
     if (customization) return tip("Autosave: map cannot be saved in edit mode", false, "warning", 2000);
 
-    tip("Autosave: saving map...", false, "warning", 3000);
-    const mapData = getMapData();
-    const blob = new Blob([mapData], {type: "text/plain"});
-    await ldb.set("lastMap", blob);
-    INFO && console.log("Autosaved at", new Date().toLocaleTimeString());
-    lastSavedAt = Date.now();
+    try {
+      tip("Autosave: saving map...", false, "warning", 3000);
+      const compressedMapData = await compressData(prepareMapData());
+      await saveToStorage(compressedMapData);
+      tip("Autosave: map is saved", false, "success", 2000);
+
+      lastSavedAt = Date.now();
+    } catch (error) {
+      ERROR && console.error(error);
+    }
   }
 
   setInterval(autosave, MINUTE / 2);
 }
 
-async function quickSave() {
-  if (customization)
-    return tip("Map cannot be saved when edit mode is active, please exit the mode first", false, "error");
+async function compressData(uncompressedData) {
+  const compressedStream = new Blob([uncompressedData]).stream().pipeThrough(new CompressionStream("gzip"));
 
-  const mapData = getMapData();
-  const blob = new Blob([mapData], {type: "text/plain"});
-  await ldb.set("lastMap", blob); // auto-save map
-  tip("Map is saved to browser memory. Please also save as .map file to secure progress", true, "success", 2000);
+  let compressedData = [];
+  for await (const chunk of compressedStream) {
+    compressedData = compressedData.concat(Array.from(chunk));
+  }
+
+  return new Uint8Array(compressedData);
 }
 
 const saveReminder = function () {
   if (localStorage.getItem("noReminder")) return;
   const message = [
-    "Please don't forget to save your work as a .map file",
-    "Please remember to save work as a .map file",
-    "Saving in .map format will ensure your data won't be lost in case of issues",
+    "Please don't forget to save the project to desktop from time to time",
+    "Please remember to save the map to your desktop",
+    "Saving will ensure your data won't be lost in case of issues",
     "Safety is number one priority. Please save the map",
     "Don't forget to save your map on a regular basis!",
     "Just a gentle reminder for you to save the map",
-    "Please don't forget to save your progress (saving as .map is the best option)",
-    "Don't want to be reminded about need to save? Press CTRL+Q"
+    "Please don't forget to save your progress (saving to desktop is the best option)",
+    "Don't want to get reminded about need to save? Press CTRL+Q"
   ];
   const interval = 15 * 60 * 1000; // remind every 15 minutes
 
diff --git a/modules/ui/heightmap-editor.js b/modules/ui/heightmap-editor.js
index 41031786..40bc55fb 100644
--- a/modules/ui/heightmap-editor.js
+++ b/modules/ui/heightmap-editor.js
@@ -28,7 +28,7 @@ function editHeightmap(options) {
     <p><i>Erase</i> mode also allows you Convert an Image into a heightmap or use Template Editor.</p>
     <p>You can <i>keep</i> the data, but you won't be able to change the coastline.</p>
     <p>Try <i>risk</i> mode to change the coastline and keep the data. The data will be restored as much as possible, but it can cause unpredictable errors.</p>
-    <p>Please <span class="pseudoLink" onclick="dowloadMap();">save the map</span> before editing the heightmap!</p>
+    <p>Please <span class="pseudoLink" onclick="saveMap('machine')">save the map</span> before editing the heightmap!</p>
     <p style="margin-bottom: 0">Check out ${link(
       "https://github.com/Azgaar/Fantasy-Map-Generator/wiki/Heightmap-customization",
       "wiki"
diff --git a/modules/ui/hotkeys.js b/modules/ui/hotkeys.js
index f7443469..4543d187 100644
--- a/modules/ui/hotkeys.js
+++ b/modules/ui/hotkeys.js
@@ -25,15 +25,15 @@ function handleKeyup(event) {
 
   if (code === "F1") showInfo();
   else if (code === "F2") regeneratePrompt();
-  else if (code === "F6") quickSave();
+  else if (code === "F6") saveMap("storage");
   else if (code === "F9") quickLoad();
   else if (code === "Tab") toggleOptions(event);
   else if (code === "Escape") closeAllDialogs();
   else if (code === "Delete") removeElementOnKey();
   else if (code === "KeyO" && document.getElementById("canvas3d")) toggle3dOptions();
   else if (ctrl && code === "KeyQ") toggleSaveReminder();
-  else if (ctrl && code === "KeyS") dowloadMap();
-  else if (ctrl && code === "KeyC") saveToDropbox();
+  else if (ctrl && code === "KeyS") saveMap("machine");
+  else if (ctrl && code === "KeyC") saveMap("dropbox");
   else if (ctrl && code === "KeyZ" && undo?.offsetParent) undo.click();
   else if (ctrl && code === "KeyY" && redo?.offsetParent) redo.click();
   else if (shift && code === "KeyH") editHeightmap();
diff --git a/modules/ui/options.js b/modules/ui/options.js
index ce3b3561..8a6c4c36 100644
--- a/modules/ui/options.js
+++ b/modules/ui/options.js
@@ -793,7 +793,7 @@ async function showLoadPane() {
   $("#loadMapData").dialog({
     title: "Load map",
     resizable: false,
-    width: "24em",
+    width: "auto",
     position: {my: "center", at: "center", of: "svg"},
     buttons: {
       Close: function () {
@@ -844,8 +844,8 @@ async function connectToDropbox() {
 
 function loadURL() {
   const pattern = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/;
-  const inner = `Provide URL to a .map file:
-    <input id="mapURL" type="url" style="width: 24em" placeholder="https://e-cloud.com/test.map">
+  const inner = `Provide URL to map file:
+    <input id="mapURL" type="url" style="width: 24em" placeholder="https://e-cloud.com/test.gz">
     <br><i>Please note server should allow CORS for file to be loaded. If CORS is not allowed, save file to Dropbox and provide a direct link</i>`;
   alertMessage.innerHTML = inner;
   $("#alert").dialog({
diff --git a/utils/polyfills.js b/utils/polyfills.js
index 369e647f..667d81ab 100644
--- a/utils/polyfills.js
+++ b/utils/polyfills.js
@@ -14,3 +14,19 @@ if (Array.prototype.flat === undefined) {
     return this.reduce((acc, val) => (Array.isArray(val) ? acc.concat(val.flat()) : acc.concat(val)), []);
   };
 }
+
+// readable stream iterator: https://bugs.chromium.org/p/chromium/issues/detail?id=929585#c10
+if (ReadableStream.prototype[Symbol.asyncIterator] === undefined) {
+  ReadableStream.prototype[Symbol.asyncIterator] = async function* () {
+    const reader = this.getReader();
+    try {
+      while (true) {
+        const {done, value} = await reader.read();
+        if (done) return;
+        yield value;
+      }
+    } finally {
+      reader.releaseLock();
+    }
+  };
+}
diff --git a/versioning.js b/versioning.js
index 67c0b12c..0772ba26 100644
--- a/versioning.js
+++ b/versioning.js
@@ -1,7 +1,7 @@
 "use strict";
 
 // version and caching control
-const version = "1.92.05"; // generator version, update each time
+const version = "1.93.00"; // generator version, update each time
 
 {
   document.title += " v" + version;
@@ -23,11 +23,13 @@ const version = "1.92.05"; // generator version, update each time
     const discord = "https://discordapp.com/invite/X7E84HU";
     const patreon = "https://www.patreon.com/azgaar";
 
-    alertMessage.innerHTML = /* html */ `The Fantasy Map Generator is updated up to version <strong>${version}</strong>. This version is compatible with <a href="${changelog}" target="_blank">previous versions</a>, loaded <i>.map</i> files will be auto-updated.
+    alertMessage.innerHTML = /* html */ `The Fantasy Map Generator is updated up to version <strong>${version}</strong>. This version is compatible with <a href="${changelog}" target="_blank">previous versions</a>, loaded save files will be auto-updated.
       ${storedVersion ? "<span>Reload the page to fetch fresh code.</span>" : ""}
 
       <ul>
         <strong>Latest changes:</strong>
+        <li>Auto-load of the last saved map is now optional (see <i>Onload behavior</i> in Options)</li>
+        <li>Save files compression (file extension is changed to <i>.gz</i>). Old <i>.map</i> files are still supported</li>
         <li>New label placement algorithm for states</li>
         <li>North and South Poles temperature can be set independently</li>
         <li>More than 70 new heraldic charges</li>