If you were to log in, you'd be able to get more information on your fellow community member.
A virus could not be written in perl and a virus would not work anyway. Any virus you could write would be specifically for a single image editor. Therefore, if you write one for photoshop, it can't attack Paint Shop Pro and so on. However, there is a really good solution to this problem. Use the Macromedia Shockwave plugin. It will display the image, but will not allow the person to save the image. True, Shockwave costs a little bundle, but it's worth the extra pennies.