I want to have a page with image thumbnails, where clicking on a thumbnail opens the image in a new window. I want to make it however so some of the images only open if a user is logged in.

I dont want to go down the route of sending coupons to someone by email when they register, which they can use to add free items to their cart and download the images that way.

Anyone know how to so this? Ive been searching around on the form but I dont exactly know what to search for?