Resolution loss editing GIFs. I've had a problem for a long time losing resolution when making animated GIFs with gimp but recently I tried editing a GIF produced by Screencast-O-Matic and if I do nothing more than change the frame rate on the animation I lose resolution. Why is that?

GIF is an old and difficult format to get good results. The easiest way to improve resolution is to reduce the dimensions of the GIF and the number of frames. Many avatars here are gifs (like mine) and you can see they are small in physical size. IMHO GIF is a finely balanced set of trade-offs.

GIFs are color-indexed. In the original GIF format, there is a 256-colors color map for the whole file. An extension was made to this to allow a colormap per frame, but Gimp doesn't support it.

So for instance if you have animation where the first frames are mostly yellow, and things evolve to mostly blue, with the extended format you can have 256 shades of yellow in the first frame, and 256 shades of blue in the last. With Gimp's original GIF format you have at best 128 shades of yellow and 128 shades of blues, so less colors to work with an things look grainy.