Try it now. Open any image, make some obvious editing changes such as changing the image size or cropping. Create a snapshot. Now click the first snapshot in the list. The image reverts to its original state. Click the second snapshot and you'll be returned to the edited version. Snapshots can be a very powerful tool, especially when used in combination with other tools like the History Brush. (We'll learn more about that later. For now, let's get back to looking at the History palette.)
Below the snapshots there is a dividing line, and a list of all the recent changes you have made to the image. You can undo any of these recent changes just by clicking the last change you want to revert to, or by dragging the tiny arrow slider that appears next to each state. The slider is useful if you're not sure how far back you need to go because it allows you to preview the changes as you move it up or down.
