Hi,
we have your Plugin install with the latest Version 3.5.1 under WordPress 4.0.1.
Now we have made a theme change and the newest version of the theme
installed The7 (http://themeforest.net/item/the7-responsive-multipurpose-wordpress-theme/5556590)
But now you can no longer use the plugin 🙁 When you save new galleries, the system stays at the White side. And before uploading images after the 2nd image is performed, an HTTP error.
When changing the theme to the default theme Twenty Fourteen everything goes perfect… unfortunately there a big conflict with the theme The7 – Would be great if you could accept you with this problem!

best regards
Jörg 🙂