AFAIK Shutterstock always used to upsize images that were submitted in smaller sizes. And if I recall correctly, there was no way to see for a buyer if the size he was going to buy was an original size or an upsized one.
Today when I looked on the buyer page of some of my images, the largest size displayed is the original size I submitted. And an additional line below that asking "Need a larger image?". When you click on that, it shows a new size ("Super") with a button with "generate" on where the download button is for the other sizes. Plus they add the explanation that this size is upsized ("Super images are generated from Large images and may take a few moments to download.")
This only happens with "small" images, so my old 8 MP images do show this functionality, my new 16 MP ones not. No idea where the limit is.
Does this translate into downsizing to improve sharpness may turn into a disadvantage?
Any opinions?