MyBB Community Forums

Hi, I'm making a forum for a site... I've got a pretty graphical banner... anyway... when I save it as a .gif, (even when I mess with the settings), it really compresses the banner, and to say the least, it makes it look really bad... so I was wondering, is there a way that I can save it as a jpg or png, and still have it show up?
I'm pretty sure I've tried saving others things as jpgs, and they won't show up...

so yeah... any help is apprecated