uses an exploit which is patched in IE, which i came up with the concept of when i was ten, but it wasnt done by anyone who was capable of it till i was just turning 17......pissed me the fuck off cuz when i was 10, i didnt know how to do it, so i forgot aboot it for a while, then i thought about it and considered doing it, then it comes out...meh!
actually, yes, you can make an image which checks the ip's of someone who is clicking it, generally, what you want to do is javascript, not java apps.....but it would either have to be something on your own site, or thru an exploit on the site in question. or else you have to figure out a way to make code execute upon loading a image....you can do this as well, look up .htaccess and forcing images to be displayed as php. for example, we have this:
http://www.hackthissite.org/articles/read/427
ignore all info on stealing cookies, and take it out, and you have a functional ip logger, get yourself access to a php running server with email ability, and you can create a php script which takes ips and emails them to you......i would suggest you ignore their php scripts and make it yourself, and just take the idea of the .htaccess file......as for a key logger, if you could figure out how to get the pic up on the front page, and somehow make it run client side scripting language of some sort (javascript?), you could grab all sorts of shite.....