Purchasing credits (along with a Pro account if you do not already have one) allows you to download selected frames from the Frame Gallery to your Photo Frame Show application.
20 credits cost $1 (USD).
Every frame is assigned an amount of credits (see Frame Gallery). When you download a frame your total purchased credits are reduced by this amount. Frames previously downloaded will not reduce your purchased credits.
Frames you download are Non-Watermarked, Web Resolution, Royalty Free.
