I am looking for a site very similar in design and function to http://www.dreamstime.com.
The front end should function very much the same as seen at the link above, with search functions, categories, ability for users to create lightboxes or "bookmark"/tag their favorite images.
Uploaded images need to have a preview function, and a watermark should be visible on the preview image.
Users purchase credits in different amounts - from 100 credits for $100 to as little as 5 credits for $5.00. These credits never expire and can be used to purchase images (just like on the site referenced above)
On the backend, I currently do not need to allow multiple photographers to upload files - this site will accommodate just one photographer, so a simple interface to upload images, add descriptions, keywords, price, etc. will be helpful.
In addition to the users purchasing credits, I also want to offer a monthly membership/subscription that users can purchase, which allows members to download a set number of images for free every month, and then they could purchase any additional images at a discounted price. (I would like to be able to offer different membership levels with different download amounts.)
All Sales and Payments will be processed via Paypal.