William Gallagher has a good article on how to edit HEIC photos without data loss. HEIC is now the default format for photos taken by iPhones.
When it was just that Facebook and the rest weren’t supporting HEIC, we thought time would sort that out. Now that Apple itself is still automatically converting HEIC to JPEG in emails, we’re wondering what the point is. We’d just like it to be possible to set up a Siri Shortcut so that we could tell our iPhones “no, no, we meant JPEG” and have it switch back and forth.
You can manage these settings in Settings > Camera > Formats. Choosing High Efficiency will mean your iPhone shoots in HEIC. Choosing Most Compatible means your iPhone shoots in JPG.
Check It Out: How to Edit HEIC Photos Without Data Loss