I don't understand the point of putting thousands of pictures on your computer? If you took them I can understand, but what is the point of having 15,000 space-gobbling A.net pictures that you could call up online at any time 24/7? I agree with crank: I look at the pictures online and leave them there!
Soontobepilot, the answer is simple. you see a picture and you like it ? ,ok then, save it on your hard disk. by doing this, you'll notice you've saved thousands of pictures you liked at that time you saw them.