How Google Picks Images for the Knowledge Panel
Bill Slawski, who has made a career out of researching Google patents for insight into future shifts in search, wrote an informative article called, How Google Decides Which Images To Show For Entities In Knowledge Panels that's worth the read.
Bill tells us that the patent describes how Google goes about choosing which images to display in the Knowledge Graph results for well known people and things (otherwise known as entities). The patent describes the process by which Google builds the relative image authority of each image and then ranks them against each other to determine the most appropriate image. Google outlines the process they use to pick images within the patent as:
To learn more specifics about this process then read the patent, Scoring images related to entities and Bill's insights within his article.
If you want to focus more on Image optimization then be sure to see our features articles:
...