Cropping can be as simple as “crop to a 250 pixel square, center based” - but few site’s have such consistently framed content. Being able to define a specific focal point (i.e. a subject’s face, the coordinates of the photo’s topic), either manually or using computer vision, means that developers do not need to sacrifice a photo’s aesthetics to get the best performance possible.
Testing was an examination of documentation for each service to see if cropping was an available feature. If it did exist, its functionality was confirmed.