Walls get moderated for more than one reason, but are approved for only one reason, so long as they will work reasonably well as computer screen backgrounds.
Yes, that is what they are 'supposed' to be.
Something that can 'work' as a back-drop to your operating system's icons, etc.
Realistically, simple, low-contrast non-distracting graphics are 'more' suited to the task than any other.
Take my two 'walls'.
Note the content...
Note it with regards to these criteria...
Note the download number...
Glory be praised...the more muted, less distracting one has twice the downloads....must mean something.
OK, the scores are a bit whacky in comparison, but I didn't rate them.
Had I, they'd be different...
To the case in point.
If it is the wall I'm thinking of, the most polite way of putting it is 'stuck an 'XP' in it for downloads'.
Quite frankly, there are other letters in the alphabet.
Last time I looked, there were 24 others.
But...
I could be wrong.