I just purchased a plan and I see some credits were used already, why?
If you used all your monthly free credits
and then decided to buy additional one-time credits you may notice that some one-time credits were already used
This can be puzzling especially when you may know for sure that you haven't run ShortPixel Image Optimizer and no additional credits should have been used.
The reason why the extra 10 used credits appear in the example above is because WordPress has thumbnails associated to each image.
So for example your account used 95 image optimization credits and still have 5 credits available. Then a request for an image and its 14 associated thumbnails (15 credits in total) is sent to ShortPixel API. The API will accept this request (there are still 5 more credits available) even though the total amount of credits needed exceeds the number of credits available. This is so that one image and all its associated thumbnails can be optimized at once.
The additional 10 credits in the example above are borrowed from the one-time credits quota even though there can be 0 one-time credits available.
Once a one-time plan is bought the credits borrowed will appear as already used as in the example above.