Put it on your bedside table, make love to another woman, and occasionally glance at the picture, making "Awe yeah! Are you catching this?" faces. It will make you feel better.
Alternatively, if you really liked her, you could destroy it in a sentimental fashion...
Tie it to a rock and throw it in a river!
Burn it, smear the ashes all over your face and have a pillow fight with yourself!
Put it in a paper shredder, print 100 sheets that say "I'm moving on," shred them, mix up all the shreds, and stuff a teddybear with them before giving it away as a gift to a small child...
You know, mature things...