For each member ?

Hi, unfortunately this plugin is not set up for your requirements.

When you say “allow my members”, are you asking if this plugin supports WP-multisite? It depends on your site’s setup.

Basically, to display the admin pages, the plugin makes use of the security capability, edit_theme_options. So, if your users can tweak their theme settings, they can see the admin panel for Photonic, wherein they can put in details about their API keys etc. That will let them use the plugin on their posts.