So it's my birthday

Don't really have much to give, and I'm not much of a puzzler either, but...well, give this puzzle a try:

Clicky

The first hint I'll give you is that you won't get much of anyone just looking at the image. Also, it's a Steam key. I'll give another hint if no one's gotten it in an hour or so. Please post hear if you've solved it and taken the key.

Sorry for being missing, intended to post another hint but I was separated from my computer all day. The next hint is that the extension is important.