Which format – alongside Camera Raw – should you store archived images in: JPEG, PNG, TIFF or Apple’s new HEIC?
PNG
How the iOS Photos app may save your PNG screenshot images in JPEG format: one mystery solved, another opened.
When you take a screenshot in iOS, it is saved in PNG format. There is no option. So why do mine come across on iCloud Drive as a JPEG?
The Eclectic Light Company 