Only semi related, but can someone explain to me how the hashing process works? Of course I get the process of hashing passwords and such, but how do you hash

Only semi related, but can someone explain to me how the hashing process works? Of course I get the process of hashing passwords and such, but how do you hash a photo so that the hash isn’t invalidated as soon as I convert it to a different format or trim a single pixel off of it or add a scrolling banner that “this video was uploaded to…”?