You can remove photos in the Manage Photos section of your account. Click on Manage Photo under the photo you'd like to remove. Then click "Remove From All Agencies".
Note: Photos marked as "paid" will be stored in a REMOVED photo folder that can only be accessed by you. You can restore those photos for use by you or talent representatives at any time. Photos marked as "free" will be permanently deleted from your profile.
Here is a helpful video tutorial that will show you how to manage your existing photos: