If you have used up all of your monthly free credits…
…and then decided to purchase additional one-time credits, you may find that some one-time credits have already been used up.
This can be confusing, especially if you know for a fact that you have not optimized any images for a while and should not have used any additional credits.
Let's explain it with an example. Say your account has used 95 credits for image optimization and still has 5 credits available. Then a request is sent to the ShortPixel API for an image and its 14 thumbnails (15 credits in total). The API accepts this request (5 credits are still available) even though the total number of credits needed exceeds the number of credits available. In this way, an image and all associated thumbnails can be optimized at once.
The additional 10 credits in the above example above are taken from the one-time credits quota, even though there can be 0 one-time credits available.
Once a one-time plan is purchased, the borrowed credits will appear as already used, as in the example above.