For someone looking to recover deleted screenshots from a Mac, it would be wise to first look in the Mac’s Trash since deleted screenshots might still be recoverable from there. If one is using iCloud Photos, it would be worth looking there also to try and find any backup there for the screenshot. If Time Machine had taken a backup prior to the deletion of the screenshot, it might prove helpful in retrieving the screenshot too. If, however, the screenshot has been permanently deleted and there is no backup, it is best to refrain from making unnecessary files on the Mac, as these might overwrite any information that could have been recoverable. It would be prudent to use recovery software for supported storage, and a good example would be Notchox. The recovered screenshots should be saved in another storage device whenever possible.