Yea i know but its easy to fake al you need is a little bit of photoshop skills and a good printer.
furthermore the photo looks to be taken in a car, like somebody bought it and is taking it home.
You're right I believe I found it how ever. Is a mod for GTA III don't think they ever finished it tho, because apart form the map it self there is little trace of it on the internet. The only think I could find was this youtube video.