So I'm trying to customize my profile, and I notice that it lets you put an image for your background. So, following the instructions at the top of the page,

Background images must come from your albums. Enter the URL to a picture in one of your public or profile albums.

I upload an image to my albums and enter the URL into the "Background Image" box. I then click save. It gives me the following message:

Main has invalid properties: Background Image

My question is how do I put an image as my profile background?

Take a look at the album your picture has been uploaded to. Click on Edit Album at the top right and then make sure that you've selected the right album Type. You should select:

Profile - Pictures used to modify your profile style

Then you can use to URL as a profile background. :yes:

:O It worked!
Thank you for your help! :D