You can now keep track of your favourite photos on Fotonomy with the new.... 'favourites' feature!
You should find it fairly self explanatory. Just click the little 'Fave' star button on any photo to add or remove it from your list. You can keep track of all your faves on your own 'My Favourites' page as well as browsing other people's favourites.
Have a play, and let me know what you think in the comments here!
Oh - and before anyone says, I've gone with the British spelling of favourites (with a 'u') - it's not a typo! :)