Our credit system is very simple. Every month you get a number of credits based on your plan. Each prediction deducts credits from your monthly total.
An image deducts 1 credit each time you make a new prediction.
Videos work a bit different. Each month you have a certain amount of minutes/seconds you can spend on video. For every video you process it deducts a certain amount of minutes/seconds off of your total. The amount that gets deducted depends on the length of your video.
Any credits that are left at the other month are saved up and thus can be used at a later point in time. Keep in mind that in order to keep your credits you need to have an active subscription.