Mugshots end up online because arrest records are public data, often scraped by...

https://wiki-tonic.win/index.php/What_is_the_Fastest_Way_to_Reduce_Reputational_Damage_from_a_Mugshot%3F

Mugshots end up online because arrest records are public data, often scraped by automated sites that profit from ad clicks. Unfortunately, once a photo is published, it spreads across multiple domains