I was having an email conversation with Stoo Cambridge, and he mentioned that he was having trouble making his Linux machine display thumbnails of Amiga IFF/ILBM files. It turns out I have a solution for him, so I am sharing it here to help anyone else.

GNOME Support

There is a versatile library and command line image manipulation tool in most Linux distributions called ImageMagick, and it supports IFF/ILBM files natively. This gives us one piece of the puzzle. The other piece is how to use this to generate thumbnails using this.

GNOME and most other desktops support the Freedeskop standard of “Thumbnailers”. These are small configuration files that tell the desktop how to generate a thumbnail for a specific mime type.

Using this information we can create a file called ilbm.thumbnailer with the following contents and put it into /usr/share/thumbnailers.

[Thumbnailer Entry]
TryExec=convert
Exec=convert %i -thumbnail %s %o
MimeType=image/x-ilbm;

This will usually require you to log out and log back in again for the files to be discovered. After this, thumbnails of your Amiga files should work!

KDE Plasma

Unfortunately, KDE Plasma does not support the thumbnailer standard. For this, a plugin needs to be written for Dolphin. Luckily, this is straightforward to do. I knocked this one up in about half an hour, and it seems to work well.

You can obtain the source code for this plugin on GitHub.

Update 2023-09-01

The code now corrects the aspect ratio of full screen Amiga images before generating the thumbnail, this is because Amigas can have resolutions such as 640×200 and 320×400 on a 4:3 screen. This is the end result: