Iben....looks like you managed to get a small image up.
Now, if you try an actual screenshot of your desktop, rather than a small icon, you'll discover that the image will be reduced to fit in the space automatically....in your case your little image was EXPANDED to fit automatically.
Normally an image is at least as big as the desktop...we are talking 800x600 or 1024x768 pixels...or something like that, saved in jpg format and uploaded.
They are a different criteria/section/placement to the screenshot section on the left.
These are specific uploads for your display via your 'Edit Account' section.
Now, is all this clear, or are you genuinely still having problems getting an upload to this particular part to work?
Lemme know, K?...