Photoshop CC: Black or white squares on my image - MacOS 10.10 Yosemite: Graphics driver problem

Just installed yosemite on my mac and I have Photoshop CC installed. Photoshop works fine, but when returning from sleep mode I.e. next time I open photoshop i get something like this when I open an image (https://dl.dropboxusercontent.com/u/2...). Moreover, the bits and pieces of the image I see are not from the picture I tried to open, but are from a picture I just finished processing....Closing PS completely and opening it again solves the issue however.
Any solutions for this annoying problem?

Imac 27" model 14,2
Intel I5 3,2GHz
8 Gig ram
VIDIA GeForce GT 755M 1024 MB