“ However the original, anonymous user stumbled onto this photograph, it appears it was taken from either the Wayback directly, or the Wayback Machine crawled the same site the user had found, and kept that webpage’s preservation for over 20 years.”

Something people used to do is to use search engines to find images with file names that indicate they were from a digital camera. You could find all sorts of interesting photos that people had uploaded to share with their friends not realising that search engines would index them.