kuro: use 512x512 icon, resolves #354644

The hicolor icon theme doesn't support bigger than 512x512 icons, so convert the original 1024x1024 one.

pkgs/by-name/ku/kuro/package.nix

@@ -10,6 +10,7 @@
   makeDesktopItem,
   copyDesktopItems,
   electron,
+  imagemagick,
 }:
 
 stdenv.mkDerivation rec {
@@ -36,6 +37,7 @@ stdenv.mkDerivation rec {
     nodejs
     makeWrapper
     copyDesktopItems
+    imagemagick
   ];
 
   yarnBuildScript = "electron-builder";
@@ -53,7 +55,8 @@ stdenv.mkDerivation rec {
     cp -r ./dist/*-unpacked/{locales,resources{,.pak}} "$out/share/lib/kuro"
 
     # icons
-    install -Dm644 ./static/Icon.png $out/share/icons/hicolor/1024x1024/apps/kuro.png
+    magick static/Icon.png -resize 512x512 kuro.png # original icon is 1024x1024, which isn't supported by hicolor
+    install -Dm444 kuro.png $out/share/icons/hicolor/512x512/apps/kuro.png
 
     # executable wrapper
     makeWrapper '${electron}/bin/electron' "$out/bin/kuro" \