The jpeg exploit is only harmfull when you view a picture in jpg (jpeg) format with certain viewers (normally only MS ones) other viewers like PSP (Paint Shop Pro), ACDSee, PhotoShop (pro) can and will display the image without the risk of infection. They just show the picture itself and do not executed any code.
In fact the tecnic to implement other info into a picture was used many years ago to communicate between a blackmailer and the Dutch police. So basicly what we are talking about is really old news. Luckely, not much people are using this technic for bad purposes. (up to now that is)