Opening a Dynamic Pop Up Window

Help! :-) Have a need for a pop up window to show images when the thumbnail is clicked. But the script I found only shows the image and no background, etc. I want to be able to have the pop up open and then send it a php created dynamic page with the proper html and image. In perl I know how to do this, by calling a perl script, sending the filename variable and returning with a generated page. But I am not as familiar with PHP. Here is the script I found: http://www.ciarasprettygoodpictures.com/gallery.php