Why does Game Development need indexed sprites?
All the trainers are .PNGs which don't have a limit on color or size it can be put into Essentials.
If this is for ROM hacks, you're in the wrong place, and I believe you wanted to post it here:
http://www.pokecommunity.com/showthread.php?t=193327
Try not to mini-mod, because that's considered spam.
I left this thread here because they're just graphics and you can use them however you want.