iMessage freezing when sending pictures

If a picture is selected then iMessaged and it hasn’t sent yet, then try to send more pictures to the same contact or group, my phone freezes and have to close iMessage and wait for first message to send before can send the next. This has happened at least half a dozen times. Also, with the new update my phone will randomly get stuck with the screen half down like it would if you tap the home button, but at times it wasn’t tapped and mostly happens on the lock screen. Have an iPhone 7 and the most recent update. Wish it was possible to undo the update! And sad it didn’t work good on a phone only a year old.