Techniques used.

For creating gifs this website uses ImageMagick's convert utility. It's quite powerful – and also quite complicated.
I found some ok looking configurations to create animations of small file sizes. But I'm sure there are better out there. If you can help, say hi!

The small gif is created by:
convert -resize 320 -coalesce -colors 16 -layers OptimizeFrame -compress lzw *.jpg output--small.gif
The big one by:
convert -coalesce -layers OptimizeFrame -compress lzw *.jpg output.gif