When I have seen other users bring this up in the past, it has been a myriad of different issues. But the easiest thing to do first, if possible, is attempt to identify if the this problem is related to a certain subset of users, or any other anything else in common with the images that you can’t view. Sometimes, it’s a user who is somehow on a slightly older version of the App and never got an update. Sometimes, it’s a user’s version of their camera software or OS version. But seeing as the email always gets the images, then it’s probably a weird formatting of the pictures file name from the users. Take a look at the raw data of which pictures aren’t displaying and I bet we can start to narrow down the issue.