I recently installed the DRUPAL MEDIA GALLERY module and really like it. Finding a simple to conifgure Drupal Image Gallery has been a thorn in my side for an age. This one works nearly perfectly - except it just will not handle COLOROBOX as its image handler because of its inbuilt integration with LIGHTBOX - a similar function but I prefer the way colorbox looks looks. So before I was forced to unisntall colorbox and integrate lightbox instead, a quick Google search showed me this simply excellent blog post by Paul Junior.
It's not often I repost someone elses blog but this one is just spot on:
Anyone who has tried to user the Media Gallery module on a site that already has the Colorbox module installed will know that they do not play well together. If you have both modules enabled, create a gallery (with lightbox capabilities) and try to click a thumbnail, the lightbox will not show.
This is because, essentially, Colorbox is being called twice, once by the Colorbox module and second by the Media Gallery module. To fix this without applying any patches or editing any code, follow these steps: