Popup images window too small - doesn't resize

Hi team,

I know, I know, I'm lame because I can't find the answer to my question, which I am sure is in here somewhere; the problem is I don't know the correct terms so searching for popup windows size results in stuff that isn't exactly relevant, given that many responses are 'install the light box instead', which I don't consider that helpful.

My problem is a shop I look after was recently hacked and I have - with your help - put it all back together. The one thing that does not work, but which worked before, was the product images/popup windows for displaying larger images does not automatically resize. It can be dragged into shape to view the image but this is a hassle and I should be able to set the popup window to size to the image (which are pretty much all the same size).

Is there a quick fix for this? The site in question is brianphillips.co.nz/zen/ and you can click any product/image to find and click the larger version link. You'll soon see what I mean.

Thanks for your help.

Dave.