The ‘Like’ as a concept is largely worthless. A ‘Like’ has no value, no cost for doling out. ‘Liking’ your content costs me nothing, so what’s to stop me from ‘Liking’ everything I see without considering how it affects the popularity of that content?
Favourites are your personal way of saving the what you love to a place where you can easily find them again.
A recommendation differs in that it doesn’t necessarily have to be a what that you love, but more so a photograph which you believe is technically good and should be seen by other people.