summer
Click on the image once, then you can use CTRL and SHIFT to zoom in and out, and the arrow keys to move around.
If you are on an Apple device, drag your finger on the image to pan around. Pinch/unpinch on the image to zoom in and out.
Woot! This is my biggest piece yet (well, that I've done in Photoshop, that is). It measures 4'x6' at 240ppi (pixels per inch). Why so big? Why not. I want to see how large I can go before I hit the limit for Photoshop CS4 and my computer's ram.