Help - pictures are black!

Hi there,

I have an issue many other people had before me: The pictures on my Sims' walls have turned black. 
I never had them in my household inventory or in any other storage, they were always on the walls. So I don't know what to do... I tried to figure out which mod is causing this, removed some that could be the issue, but so far nothing has worked. 

What can I do to fix this? I'd really appreciate advice. Thanks in advance!