Resources to learn how to make Sticker GIF apps for iMessage?

Hello, I'm currently learning how to make Sticker App's of cartoon characters that move like GIFs. I've run into a problem with getting a smooth motion combined with the size limited. I've tried to compress each individual frame but I can't seem to get it right. I've looked online for resources and came up empty handed. Anyone who can help in any way would be greatly appreciated.