Hi Jack_Ryan,
Thank you for posting in Apple Support Communities! Are you able to view any other photos from Messages? Has your iPhone been restarted? You can close out the Messages app prior to restarting it as an additional troubleshooting step.
To close the app, swipe up from the bottom of the screen to the middle on the Home Screen and swipe to locate the Messages app. Once located swipe up on the app preview to close it out completely.
Close an app on your iPhone or iPod touch
Once closed out, you can press and release the volume bottom and press and hold the side button until the "Slide to power off" button appears. After powering off, wait about 30 seconds and power your device back on.
Restart your iPhone
Test to see if this continues.
You should also confirm there are no updates that need to be installed by going to Settings > General > Software updates. Be sure to back up your data prior to installing any updates.
Update your iPhone, iPad, or iPod touch
Have a good one!