HEIC files are native to Apple iPhones though are not widely accepted within other platforms.
Convert batches of iPhone .HEIC images into optimized JPEGs using JPEGmini Pro
Converting a batch of .HEIC files is as easy as drag & drop.
Take your .HEIC files or folders and drop them onto the JPEGmini window or icon.
You can choose from, optimized originals or export to a folder.
When you choose ‘optimize original’, JPEGmini will replace HEIC files with optimized JPEG files.