For the last 2 days all imported photos are coming up as black
I don't know what's happened but all the photos I try to import have for the last two days opened up as totally black. The photo is there as I can see it as the background image in the layers panel. I can't paint on the photo either yet I can see any painting in the layers panel thumbnail. I have never come across this before. I don't know whether it's a fault with the Photoshop CC application or a setting that has been activated somehow without me knowing and I don't know how to turn it off. Please can someone help!!