Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I just tried it by pressing on the photo in messages and holding it, it gave me options, I selected More.. and the trash can appeared on the lower left and allowed me to delete it.
Hope that helps
 
AND, you have to do them one at a time. Can't do them in bulk like you used to be able to do prior to iOS 13. Really annoying
 
  • Like
Reactions: Weaves
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.