Revert changes to PDFs and images in Preview on Mac
Preview periodically saves “snapshots” (called versions) of your PDF or image. You can view the file as it appeared in the past and revert to a previous version.
Revert to the last saved or opened version
Go to the Preview app on your Mac.
Do one of the following, depending on your previous actions in the file:
Choose File > Revert To > Previous Save [date, time].
Choose File > Revert To > Last Saved [date, time].
Choose File > Revert To > Last Opened [date, time].
Browse, restore, or duplicate previous versions
Go to the Preview app on your Mac.
Choose File > Revert To > Browse All Versions.
To browse through versions, click the arrows next to the previous versions or click a tick mark on the timeline on the right side of the screen.
When you see the version you want to revert to, do one of the following:
Restore the file to that version: Click Restore.
Create a new file from that version: Press and hold the Option key, then click Restore a Copy.
If you decide you don’t want to revert the file, click Done.
For information about editing iCloud documents, see If document versions conflict in iCloud Drive.