No one that I've seen takes automated screenshots of webapps or games or what have you at pre-determined timestamps to make sure the app looks pixel-identical with every change.
(regardless of the method; the SHA'ing isn't the point here, the point is that it's a shortcut instead of "inspect the image for any regressions", since we don't need to inspect the image at all if it is identical)
No one that I've seen takes automated screenshots of webapps or games or what have you at pre-determined timestamps to make sure the app looks pixel-identical with every change.
(regardless of the method; the SHA'ing isn't the point here, the point is that it's a shortcut instead of "inspect the image for any regressions", since we don't need to inspect the image at all if it is identical)