I've had a similar problem whilst trying to run tests on a second hand Mac mini (Late 2014). I tried holding D, alt-D, cmd-D, cmd-R, alt-cmd-R, and two different wired keyboards, but each time the machine would just boot to the normal login screen.
I then reset the SMC (on this machine: unplug power cord, wait 15 secs, replug, wait 5 secs, power on - see ...
Lol to snapselect they are looking for duplicate finder not editing photos
I use photo fixer pro and works well too bad in the past with iphoto there was an auto select photo app now you have to select each one and for me its a pain why well because i have 80,570 photos mixed with videos