I guess your phone is a Samsung (or possibly Nokia)?
The proprietary .HEIC format is by no means universally adopted and unlikely to be. I would strongly advise turning off High Efficiency in the camera settings to return to JPEG.
Edit: Image got there before me. My phone did this a couple of years ago, I don't think it was an update, the change happened halfway through a visit to Salisbury and I had to convert an afternoon's worth of pictures back to jpg.
