Thread:Help talk:Gallery format/Overlay images not available for displaying

I may be missing something from the examples and the docs, but I cant get the gallery format to display the full size images with the overlay option. I do get the results and their thumbs but when I click on them, I get the "The requested content cannot be loaded. Please try again later." message. Inspecting the HTML I see that the "href" attribute on the  element is empty, which is why the image is not loaded on the fancybox. Any suggestions? Thanks in advance :)