I have the same problem. When the painting is selected, the thumbnail in the lower right corner (the one with item name and price) also still has image, but it showed blank canvas on the wall.
Already tried saving the room with painting to My Library but don't work. If looked at from Library, the painting is obviously still has image, but when the room is placed in the house, the result is a blank canvas.
I just started playing again after a few months hiatus. Currently, I have 5 paintings from reference. Four paintings from a few months ago, which last I played there was no problem. Now, those paintings showed the image but the price suddenly dropped and fluctuated (from a few hundred to a few thousand) every time I moved them to different spots on the wall. The last painting was newly created and it became blank canvas every time I reload the game, I have tried painting 3 times and still the same problem.
