Ok, so i've been trying to make a new 72x72 pixel avatar, yet I can't get anything to come even close to fitting the 7000 byte limit at that size. Any suggestions? I never had this trouble on my PC, I'm using a Mac now.
What program are you using? If you're in Photoshop, you should be able to decide the quality of the avatar you're saving. Pick near to the lowest quality because for an avatar, it doesn't matter. Otherwise, there's a couple options for simple cropping and resizing, I've used both EasyCrop and PhotoComplete, they both allow you to choose the quality of the output.
Oh, and if I'm not mistaken, PNG files take up more space than JPEG, so that might be a problem too.
I've never used any of these, I just stick with PhotoComplete. It still lets you use it after the trial is finished, but you can only make two alterations to the original photo, but since all I ever do is make avatars and icons, it's not a big deal. For more advanced editing, I found some: