] EasyNews, a provider of Usenet newsgroups, said it has
] identified two JPEG images that take advantage of a
] previously identified flaw in the way Microsoft software
] handles graphics files. Windows users could have their
] computers infected merely by opening one of those Trojan
] horse images.

The sample toolkit is interesting. Code in the wild, more so.

Trojan horse exploits image flaw | CNET News.com