added multiple icons

flake.nix

@@ -31,6 +31,8 @@
 
       comment = "Advanced text editor for script writers.";
       categories = ["Office" "TextEditor" "Utility"];
+
+      mimeTypes = ["application/x-${name}"];
     };
   in {
     packages.${system} = {
@@ -43,10 +45,16 @@
         };
 
         extraInstallCommands = ''
-          mkdir -p $out/share/icons/hicolor/1024x1024/apps/
+          mkdir -p $out/share/icons/
 
           ln -s "${desktopItem}/share/applications" $out/share/applications
-          ln -s "${icon}" $out/share/icons/hicolor/1024x1024/apps/${name}.png
+
+          for dimension in 128 256 512; do
+              dimensions=''${dimension}x''${dimension}
+              mkdir -p $out/share/icons/hicolor/$dimensions/apps
+
+              "${pkgs.imagemagick}/bin/convert" ${icon} -resize $dimensions $out/share/icons/hicolor/$dimensions/apps/${name}.png
+          done
         '';
       };
     };