Greene and Bmiller have it right.
While it would seem to make sense, keep in mind this site doesn't store any photo's. All it's doing is *referencing* the picture from another internet site. That could be picassa, photobucket, or any number of hosting sites. Your PC, while on the internet, is not publically acessible. At least I hope for your sake it's not otherwise you have a big security problem.
It's a lot easier than it looks. Open an account on a photo hosting site (not snapfish!), upload your pics to that site, then reference the link on this forum.
In the case of photobucket, it will give you the IMG code already. So once you upload there, you can literally copy and paste the IMG code into a post here.
Once you do it once, it's gravy.