You can view the images that your client has hidden in a gallery by doing the following:
- From the main menu click on Photos » Galleries.
- Locate your client's gallery and click on Photos » Manage Categories.
- Click on the name of a category to view the photos within it.
- Any image that's been hidden by your client will have an icon of an eye with a slash through it displayed with it.
Note: You aren't currently able to un-hide images from the admin area. That can be done by following the steps outlined in our article, here: How can my clients un-hide a hidden image?