I have used Time machine back up and as I wish to delets photos on my I mac I want to confirm that I have backed up ok. However when I go into Time Machine and attempt to open I photo I get the message ' cant see becasue its in a time machine back up'.
How do I get to see whats in the back up... any of them
Time Machine is backup, not an archive. You should not use it to keep permanent copies of things you have deleted from your main disk. Once the original is gone, the Time Machine copy will not last forever. If you want to keep a permanent copy of a photo "offline", you must make a copy of it somewhere.