First change the default location of where your screenshots are normally saved. Default location is the Desktop. Create a folder Screens or whatever you like to name it and run the following commands in the Terminal application :
In my example I created a folder Screenshots on the Desktop, change it to the folder you created. Test is my username so change that as well!
Code:
defaults write com.apple.screencapture location /Users/test/Desktop/Screenshots
killall SystemUIServer
The screenshots will now be saved in the new default location eg in my case the folder Screenshots. Create a new folder for your backups eg in my case a folder ScreenshotsBackup on the Desktop.
Create a folder action and attach it to the new default folder eg in my case the folder Screenshots.
Folder action code :
Code:
on adding folder items to this_folder after receiving these_items
--change the following line to where your ScreenshotsBackup folder is located
-- eg "Macintosh HD:Users:yourusername:"
-- As you can see in my case it's a folder ScreenshotsBackup on the Desktop
set theDuplicateFolder to "LeopardFirewire:Users:test:Desktop:ScreenshotsBackup:"
--set theDuplicateFolder to (path to desktop as text) & "ScreenshotsBackup:"
repeat with i from 1 to number of items in these_items
set this_item to item i of these_items
tell application "Finder"
duplicate this_item to theDuplicateFolder
end tell
end repeat
end adding folder items to
Any screenshot you make will be duplicated to the backup folder.