ZOOMING ALL YOUR TILED IMAGES AT ONCE

If you've chosen to tile your open windows (in the Window menu, under Arrange, choose Tile), in Photoshop CS you get some hidden functionality. If you want all the tiled images to be displayed at the same level of magnification, just hold the Shift key, grab the Zoom tool, zoom in on one of the images, and all the other tiled images will jump to that same magnification. This is great when you're trying to compare a number of similar images for detail.