look at bottom right of the right crutch. thats how you 100% know its photoshoppped. Also, another way open up the image using wordpad/notepad look in the first line and it will show the program used to either open or edit the photo. thats how i always tell.
EDIT: It was photshopped at 2008:04:04 12:18:10 using Adobe Photoshop CS3 Windows. So because it was just photoshopped mere hours ago my guess is the guy who posted this photoshopped it.