Wall art from the Gallery turned blank canvas

I downloaded some beautiful wall art done by other simmers like #juwels64 #catatron16 #AliasLTS.  After I put it in my house walls, all was ok.  The next day, when I loaded my game again, all the wall art, was just a blank canvas.  Today I tried again, with different pictures, different simmer, the result was the same.  After saving the game and loading again, all the pictures turned in a white canvas.  What's going on?