This is pretty much for my own reference, so please ignore if you already know these. 🙂

Batch convert a directory of PNGs to GIF:

mogrify -format gif *.png

Resize everything in the directory:

mogrify -resize 96x96 -colors 128 -depth 8 *

Remove transparency (can make filesizes bigger, so don’t do this if you don’t need to):

mogrify -resize 96x96 -colors 128 -depth 8 -background white -flatten *