Your Main Clients can hide media from their gallery. You can choose to delete the hidden media if you desire. The process can be done by filtering the hidden media and selecting all to delete:
1. In the Photos & Media tab of the gallery, click the Filter & Search button in the top right.
2. Click Client Selections and in the drop-down menu, select to filter the photos to only show the Client Hidden.
3. You will be shown any of the images hidden within each section of the gallery. Click Select All. Then select Manage Photos in the menu and click Delete.
4. Click Yes to confirm that you would like to delete the selected photos.