Well, you never know on the internet, but I think it's real. There's a whole series of them. Proportions probably vary a lot depending on breed and age, and of course camera angle; this one looks to be very young (w/the woman's hands for comparison), younger than in most baby roo pictures where they've likely already "grown into" their feet a bit more.
http://www.ebaumsworld.com/cute-baby-kangaroo.html
Edit: Here's a random one from elsewhere, it's probably older, but still has pretty long feet, from that angle, anyway.