In the settings app. settings> watchprosite> Watchprosite needs to have access to photos as in the following image:. I was able to replicate the crash if i turned off access to photos. It shouldn’t crash. it should prompt you to grant access to photos. So...
at first i didn't have the photos and camera in my settings, had to draft a dummy message and insert a picture from the library or take a picture from the camera for it to appear.