The iMac in question is quite old now, maybe 2009? Not sure. Anyway, it has been updated over time to the newest OS and now runs very sluggish. I want to internet recovery it back to original OS and start fresh to speed it back up again. This is not a problem, I can handle this. My worry is with my photos which are now condensed in the new Apple Photos app. How do I back these up to add them back to the old iPhoto app after the restore? Are they backwards compatible? Can I simply drag the PhotosLibrary.photoslibrary file in my pictures folder onto an external HDD and then drag it back over to my newly formatted machine with an old OS as I would normally do if I was formatting it back to a new OS? Will iPhoto will simply add them all no problem like the new photos app would on a clean new OS machine or am I going to run into problems going from a Photos library to an iPhoto library? Thanks to anyone that can help me.