(03-09-2018, 09:27 AM)rich2005 Wrote: It looks awful because a gif file can only contain a maximum 256 colours.

You have 4 very different images (I took these from Google), each with thousands of different colours.

Make sure you start off in RGB mode, look at the top of the Gimp window to check.

might look like this: https://i.imgur.com/kBkZGy7.jpg

The four images have to be reduced to 256 colours. Exporting to a gif gets blocks of solid color.

like this: https://i.imgur.com/Azn5ToJ.jpg

To get around that, convert your layered image to Indexed Image -> Mode -> Indexed before exporting to an animated gif. Set the option for dithering

as shown here: https://i.imgur.com/cQLhggO.jpg

Now export that as an animated gif, you still only have 256 colours but those are now in small graded areas.

edit:
If you want better than that, Gimp is not the tool. It is possible to have an animation where each 'frame ' still only has 256 colours, but a different set of 256 colours for each frame (Gimp can only use 1 set of 256 colours for everything). The tool for this is gifsicle, it is command line, you need to study how it works. https://www.lcdf.org/gifsicle/

(03-09-2018, 09:57 AM)Ofnuts Wrote: Also, best not use Gimp for this... Gimp only supports the original GIF format, with a color map of 256 colors common to all frames. A more recent extension of the format allows a 256-color color map per frame. The old format isn't much of a problem for real animations where all frames are variations of the same and therefore share a lot of colors, but doesn't really cut it for slide shows.

Quote: I have 3 different options for dithering in the drop-down, and also an option for dithering of transparency… Which of these do I use?