I recently made a change to my site and added the ability to Print and email photos from my photography collection. I'm using a service called FotoMoto and it's really very simple, just add a line of code to your web page and you're done!
Almost.
I'm hosting my web sites under Dot Net Nuke (DNN) and my galleries are using Ventrian's Simple Gallery. It took a bit of trial and error but I finally ended up putting the code in the PopUp module and then having to force the system to use PopUp instead of SlideShow. But it works nicely, adds an link that allows you to send a postcard or to buy a print.
I really set it up more for the post cards then anything else. But hey, if you really want a picture to grace your wall, I'm not going to say no ;)
Peace, gentle readers