Correcting mistakes

Most operations can be undone if you make a mistake. Alternatively, you can restore all or part of an image to its last saved version. But available memory may limit your ability to use these options.

For information on how to restore your image to how it looked at any point in the current work session, see Reverting to a previous version of an image.

To undo the last operation:

Choose Edit > Undo.

If an operation can't be undone, the command is dimmed and changes to Can't Undo.

To redo the last operation:

Choose Edit > Redo.

You can set the Redo keystroke preference to be the same for Photoshop and ImageReady. In the General section of the Preferences dialog box, select a preference for the Redo key. You can also set the key to toggle between Undo and Redo.

To free memory used by the Undo command, the History palette, or the Clipboard (Photoshop):

Choose Edit > Purge, and choose the item type or buffer you want to clear. If already empty, the item type or buffer is dimmed.

Important: The Purge command permanently clears from memory the operation stored by the command or buffer; it cannot be undone. For example, choosing Edit > Purge > Histories deletes all history states from the History palette. Use the Purge command when the amount of information held in memory is so large that Photoshop's performance is noticeably diminished.

To revert to the last saved version:

Choose File > Revert.

Note: Revert is added as a history state in the History palette and can be undone.

To restore part of an image to its previously saved version (Photoshop):

Do one of the following:

• Use the history brush tool to paint with the selected state or snapshot on the History palette. (See Painting with a state or snapshot of an image (Photoshop).)
• Use the eraser tool with the Erase to History option selected. (See Using the eraser tool.)
• Select the area you want to restore, and choose Edit > Fill. For Use, choose History, and click OK. (See Filling and stroking selections and layers.)

Note: To restore the image with a snapshot of the initial state of the document, choose History Options from the Palette menu and make sure that the Automatically Create First Snapshot option is on.