Get the script at http://iannet.net/lj/algae.pl . The test journal is noisetube.
Note that perl is not my native language. The code, put baldly, sucks, and there isn't very much functionality. This is just a proof-of-concept. I plan on adding error handling, more generalised image support, an external config file. . . stuff like that. I also want it to say meaningful things to the user.
Of course, I'd rather not have to turn it into an actual program at all. It sounds like work. If anyone's written a better aim->lj bridge, I would love to hear about it. My web searches didn't turn up anything.