1. Use the following syntax with the heif-convert command to convert a photo. Simply supply the name of the input file (the HEIC photo) followed by the name of the output file (the new JPG or PNG photo).

$ heif-convert image.HEIC new-image.jpg

or…

$ heif-convert image.HEIC new-image.png

2. The -q option will control the quality level of the output image. To keep your converted photos looking sharp, you should use the -q 100 setting to convert at maximum quality.

$ heif-convert -q 100 image.HEIC new-image.jpg

3. If you have a lot of HEIF photos to convert, you can use a Bash for loop to bulk convert hundreds or thousands of HEIC photos at once.

$ for f in *.HEIC; do heif-convert -q 100 $f $f.jpg; done

4. If you have HEIF files scattered throughout subdirectories, you can use the find command to traverse subdirectories and convert every .HEIC (or .heic) file that it finds.

$ find . -iname “*.heic” -exec heif-convert -q 100 {} {}.jpg \;