In case it’s useful to you, this is the problem I get when using the plugin with WP4:
The lightbox functionality works, but instead of displaying my jpg image within the lightbox that opens, it displays a massive amount of text characters that starts with the below snippet. I know that the link to my image works because I can option-click and open the image in a new browser tab without problem… so the plugin is doing something to mangle the image file.