Well, that depends on what picture you're talking about. The picture of a glest unit is your rank, and it'll change as you post more, and the picture that can optionally be put up (like my OMEGA picture) is placed from the profile menu at the top of the screen.
That picture must be less than 4 kb (VERY small) and be smaller than 64x64 (might be higher, not sure) Lastly, the picture must be a link to a picture, you can't just upload it normally. Use an image hosting site to upload it.
