Apple introduced a new image file format (heic) and didn't warn anyone. We had this problem at my work too with a couple of our apps. I'll set the forum to allow this file type to be uploaded, though I cannot guarantee that everyone will be able to view your images. Apple has less than 1/2 market share (which is reducing over time) with their iphones though continues to release features that only work on iphones.
This is a pain in the backside.