After looking at the gigapixel thread and following the link to an image from the camera, I decided to make a thread for a scavenger hunt.
I'm thinking to describe a section you need to give a general description of what's in the picture, and what zoom level your at. Every couple of days or so, you can then give a hint about it's location until someone finds what you were looking at. To prove you found it you must take a screenshot and post the image. If you get it right, it's your turn to find something.
Easy eh? Kinda like I spy or something like that.
Zoom Level: Max
Object: Tower with clock face showing the time as 3:14
I think a better way to do this will be to just double post when you find something. The first post will be showing the picture you were finding including the upper corner location box. Your second post could then be the picture you want people to find with a cropped image that only has to include the zoom bar and whatever thing you want to be found.