Haha this is quite a good idea...
If scrolling through my past pictures on Facebook you will see the same holiday but with a different girlfriend (about 3 different situations) and I always feel awkward when starting to date someone else whether they would feel weird about it.
But although it is quite good to hide them, it's still part of my past - it's not (necessarily) like I'd want to delete them completely from my life and mind.
I'm keeping my pictures up, if a future GF tells me otherwise, I'll know what to use to do it easily :)