They can recognize the dog whether it's a small part or a large part of the picture - size doesn't matter for this technique. It can also classify the dog by breed. CNN systems have also been developed to help clinicians do their work including selecting cellular elements on pathological slides, correctly identifying the spatial orientation of chest radiographs, and, as Dr. Peng mentioned, automatically grading retinal images for diabetic retinopathy. So let's open the deep learning black box to understand how this works.