Minimum, maximum image size

Could not find any thing in an forum search, and the bug reporting forum seemed to be a better place for just bug reports and not questions, but simply what are the file size minimum and maximums for images? as well as minimum and maximum dimensions? i've been trying to upload a few images and they all seem to be too small.

I found it annoying that it wouldn't let me use my avatar because it was too small.

The same here, I had to actually used my own picture instead, because my avatar from gamespot was considered to small.

Yeah all my better avatars were too small :(

It's really weird, I have uploaded HUGE images (more then 4k), and they worked, while others get minimized... I guess they have a max width or height, and when you reach that, the image gets scaled down significantly.