Problem with pictures on the site

Friends,
I'm having a picture problem with the site. If you click on a pic to see it full-size, the resulting pop-up window is the wrong size for larger pics. It's no longer resizing on it's own to accommodate the full picture. I'm not sure how long this has been going on, but I think it's a recent problem (though the problem is occurring on old pics as well). I've altered the last couple of posts to allow scroll bars at least, but that's not something I want to keep doing. Plus it looks crummy. I'll throw up another post when the problem is fixed.

Rich