Just upgraded to WordPress 3.5 and upgraded to latest version of NextGen. When I did that, couldn't upload any new images as it wouldn't let me choose a gallery. Also, wouldn't let me view/edit any galleries. Deactivated all plugins. Now I can view galleries and gallery list is available on image upload. But, everytime I upload an image, it looks like it's working but does not load the image. Also, won't let me add any new galleries. No problems at all prior to update.