Many, but not all, of the pictures I have taken with my iPhone XR that I got last May are in the HEIC format. I took hundreds of photos last Otober in Greece which I pretty much edited on the phone. Downloaded them onto computer (Max OSX El Capitan 10.11.6) and can't look at many of them. I switched to Camera >most compatible, so everything since is in jpeg. However, as an artist, I often use my photos for reference and I can't see them and/or get them to print. When I want to print from the phone, it can't be bigger than 5 x 7 (at least as as I can figure out). I need to be able to see the pics, and print them as large as I want.