There are a lot of ways to undo in Photoshop, but here are three of our favorites.

  1. Ctrl-Z (or Command-Z) to undo the last action you performed on the layer or object you want to revert to.
  2. Option-Command-Z (or Option-Command-X) to undo all the changes on the layer or object you want to revert to, including any changes made since the last time you Undoed it.
  3. Shift-Command-Z (or Shift-Command-X) to undo all the changes on an entire document, including any changes made since the last time you Undoed it.