HEIC is a killer.
I'm still on iOS 10.1.1, and can not open HEIC files others share in iMessage. They are shared from iOS 12 beta. It's ridiculous.
They look like this.
iPhone 5, iOS 7.0.4
Messages are supposed to share media files in a more compatible format:
See: Using HEIF or HEVC media on Apple devices - Apple Support
When you share HEIF or HEVC media using other methods, such as AirDrop, Messages, or email, it's shared in a more compatible format, such as JPEG or H.264.
But if you can, upgrade to iOS 11, if you can and have to share media files with people, who are using HEIF files.
And tell your friend who are using beta software, to be more considerate. They should not be sharing HEIF files with people, who are not running compatible systems.
