Just thought I'd share this with the people here, feel free to remove/move this if it conflicts with any kind of rule.

Since I really wanted a nice a crisp image of my PSN avatar (one of the avatars that came with the Mortal Kombat Kollectors Edition) on my PC, I figured out how to get them.
It's really very simple, visit the PSN webpage, login and either copy the following piece of Javascript into the URL bar of your browser or use a Javascript expression parser (such as Firebug for Firefox):
javascript:sceaUserInfo = readCookie("SCEAuserinfo"); getSceaUserInfoKeyValue(sceaUserInfo, "psAvatar");

That should give you the URL to the current avatar that you're using.

My avatar:
URL: http://static-resource.np.community.playstation.net/avatar/3RD/UP10181102MK2_C9E25BF2F0FC5B25480E_L.png