Possible crash fix with editor saving

core/src/mindustry/maps/Map.java

@@ -31,7 +31,7 @@ public class Map implements Comparable<Map>, Publishable{
     /** Map width/height, shorts. */
     public int width, height;
     /** Preview texture. */
-    public Texture texture;
+    public @Nullable Texture texture;
     /** Build that this map was created in. -1 = unknown or custom build. */
     public int build;
     /** All teams present on this map.*/

core/src/mindustry/maps/Maps.java

@@ -238,10 +238,13 @@ public class Maps{
                 }
 
                 Pixmap pix = MapIO.generatePreview(world.tiles);
-                mainExecutor.submit(() -> map.previewFile().writePng(pix));
                 writeCache(map);
 
                 map.texture = new Texture(pix);
+                mainExecutor.submit(() -> {
+                    map.previewFile().writePng(pix);
+                    pix.dispose();
+                });
             }
             maps.add(map);
             maps.sort();