Since Mac OS 10.7 Lion installer creates a hidden Recovery Partition on your boot device. By default this partition is hidden in the Disk Utility’s device and volume listings. You can reveal these hidden volumes in Disk Utility using the Debug menu, but first you’ll have to enable the menu with the Terminal command:
defaults write com.apple.DiskUtility DUDebugMenuEnabled 1
Once enabled, open Disk Utility and select Show Every Partition from the Debug menu. Your hidden Recovery and EFI partitions should now be visible and available for imaging, etc.