Bird's Eye View
When you're zoomed in on an image so tightly that you're only viewing a fraction of its contents, press-and-hold the H key and then click-and-drag your mouse to temporarily zoom out and see the full contents of the image. A rectangle will appear to indicate which area you were previously viewing. Drag that rectangle to a new location and release the H key to quickly zoom into the new area. This is a great way to quickly navigate a large document.