Implemented own blob to buffer function, fixed permission bug by creating copy of map file

src/modals/SelectMapModal.js

@@ -11,6 +11,7 @@ import MapSettings from "../components/map/MapSettings";
 import AuthContext from "../contexts/AuthContext";
 
 import usePrevious from "../helpers/usePrevious";
+import blobToBuffer from "../helpers/blobToBuffer";
 
 import { maps as defaultMaps } from "../maps";
 
@@ -140,11 +141,14 @@ function SelectMapModal({
     }
     let image = new Image();
     setImageLoading(true);
+
+    // Copy file to avoid permissions issues
+    const copy = new Blob([file], { type: file.type });
     // Create and load the image temporarily to get its dimensions
-    const url = URL.createObjectURL(file);
+    const url = URL.createObjectURL(copy);
     image.onload = function () {
       handleMapAdd({
-        file,
+        file: copy,
         name,
         type: "file",
         gridX: fileGridX,