Well, I found out the hard way tonight that if you use the flickr publishing application with the new Iphoto (which I just started implementing a few days ago), flickr references the actual iphoto file. I deleted some pics b/c my laptop is 4 years old and lacks a lot of memory (yeah, my ipod has almost 8 times the memory of my laptop!!), and it messed up a bunch of my posts where I had published photos to flickr directly from Iphoto. If you do that, watch out!!!