I'v e been using a script for pop-ups for several years, and it works fine in FF.
I noticed the other day that in IE7 it's cutting off the right side of the image. I don't see anything obvious, but I don't know much about Java, so I'm hoping someone can tell me how to fix it.
One page is at: http://www.thomasddaviesarchitect.com/projects.html
The code is right on the page.
Considering not everyone here uses Windows as their primary operating system; posting a screenshot and the relevant piece of code would help you in getting quick assistance. Also since you mention cutting off the image, it might just come out to be a CSS issue if you are applying some sort of style to the newly opened window / image.