Last week I had to convert the image files with heic extension on my iPhone to jpg. After researching for a few hours, I learned that the best and cheapest way is to do it myself.
First, we include Magick.NET-Q16-AnyC library in our project via nuget. https://github.com/dlemstra/Magick.NET
Then we take all heic files in the relevant directory and convert them to jpg.
foreach (var item in Directory.GetFiles(@"D:\Apple\105APPLE\", "*.HEIC"))
using (MagickImage image = new MagickImage(item))
var finfo = new FileInfo(item);
// Save frame as jpg
image.Write(@"d:\apple\images\" + finfo.Name.Replace(".HEIC", ".jpg"));
// image.Write(@"d:\apple\images\" + finfo.Name.Replace(".HEIC", ".png"));