I just installed 13.0.3 upgrade for 64 bit and now when I resize an image to, say 800 x 600 pixels, the resulting image is very small. To get the image to display in the window at the same size (100%) as before the upgrade I have to zoom to 200 - 300%, and get the associated pixelation. Nothing else on the computer has changed (i.e., display preferences) to my knowledge. I am using a rMBP running OS X 10.8.2. Very frustrating because this is a change in behavior after the upgrade. The screen shot below shows what 100% zoom looks like now, which is about 1/3 the size an image like this used to be prior to the upgrade.
