Is there a way to get a timed image change (from one image to another) on a single image, within a gallery block?

Hello,

I'm looking for help in trying to get a single image (within a gallery block) to change out to another image, or more, and timed to change after 3 seconds or so. Right now, I'm using GIF's to do this (but it takes away from the image quality), so I'm wondering if there's another way through custom code and using JPG's. Thanks in advance!