HEIC photos will not upload for printing
I have a MacBook Pro 15 (in late 2011). MacOS is High Sierra 10.13.6 Many of my photos are HEIC rather than Jpeg. I uploaded photos to Walmart for printing. All the jpegs uploaded but the HEIC photos will not upload. I have read and followed instructions about going to Photos on my 8+ phone and checking "Download and Keep Originals" but there is no change. I also read that the IOS system should be 11 or higher. Mine is 10.13.6. Don't think it will upgrade higher. How can I print my HEIC photos?