Using a complex set of algorithms, reverse image search engines like Google, Bing, TinEye, Yandex, and Baidu identify a photos unique features like colors, points, lines, and textures and attempt to find other images in their index that are visually similar.
Search engines like Google and Bing use programs known as spiders, crawlers, and robots to scour the internet searching for publicly available content to index, including images. Nearly ten years later, it’s anyone’s guess just how many photos are floating around on the web certainly many billions, probably hundreds of billions, with millions of new additions every day. How many images are on the internet? It’s impossible to say for sure: by 2010, Google had indexed more than ten billion images.
