The Subscription option is available only for Stock section. Because the Stock section is the only one that has system managed prices the subscriptions will only work in this case.

Subscriptions are designed so you can offer your customers the possibility to get Stock photos at lower prices. Depending on the subscription purchased the user will have a specific number of free downloads for a certain number of days. As an example a user may purchase a 7 day subscription with 10 downloads/day at 59USD.

If the Stock image price is 1USD he would gain 11USD as the price of 7*10 (70) images without the subscription would be 70USD.

There are 4 low volume and 4 high volume type of subscriptions. They can be set from the administration Subscriptions section.