Aseprite thumbnails appear only in .aseprite but not in .ase

In case that the aseprite-thumbnailer (now included with Aseprite installer) shows only thumbnails for .aseprite files, and not for .ase files. You can:

  1. Open regedit
  2. Go to Computer > HKEY_CLASSES_ROOT > .ase
  3. Check that “(Default)” value is equal to “AsepriteFile”
  4. If it isn’t, you can double-click it to modify it and set it to AsepriteFile