Problem with Photo Gallery with XML!

It works great when I download it. Even when I download the pictures from the website and put it on my local machine it works fine. The problem is when I try to insert my own pictures they don’t show up after I edit the XML file. What stranger is my pictures only show up if I name them the same as your original example ones. For instance if I name my picture “kresge.jpg” and put in on my local machine it shows up. Its really strange. Any Ideas?