We appreciate you checking, Jory-USA.
Thanks for explaining more on the chain of events to get those pictures to you as well, we understand why testing another type of attachment might be problematic.
So, that being said. Let's try one more thing here to rule out the original sender and then we're going to have you reach out to Apple Support to continue troubleshooting.
This sounds more complicated than it is since we’re writing it:
From your Comcast account on your iPhone send yourself a photo to your Gmail account, not a screenshot. Open it on your computer in Outlook and then forward it back to your Comcast account and open it on your iPhone.
What happens? You may be wondering why. That’s a fair question. As we’re isolating, we need to take out specific variables. The one we can’t control for right now is the original sender, their device and how they are getting the pictures. But if everything works during this final test, we would know that the issue initiates with the original sender.
Then to continue troubleshooting, we’d like to have you reach out here: Apple - Get Support
Thank you.