If I interpret yosol correctly, he's asking for something that I know I use in PHPGenView (open source genealogy app). The Admin can assign Editing rights to a user however, not Accept rights. That means all Edits must be approved by the Admin before they actually appear. In ZP's case, it would be the images. As a user of yosol's site, i would be able to upload an image (he assigns that permission) however, he'd have to approve it before it can be openly viewed.
In the case of genalogy, prevents info being uploaded that may not be totally accurate, invasion of privacy and more. PGV goes as far as separating Edit privileges and Edit & Accept. The latter would allow the user to post and publish the data without the Admin's interception.
With photos, sizing could be problem (I upload a 3mb image!) or maybe copyright, etc. So, not a bad idea.
That is, assuming I'm understanding yosol correctly <SMILE>