RAW images imported from a camera may convert to JPEG because of the settings on your Mac. You might have disabled the ‘Download Originals to this Mac’ option in Photos app or have turned on ‘Optimise Mac Storage’ in Photos, due to which Mac keeps the smaller JPEG files. Also, if you have shot pictures using RAW+JPEG option in camera, then too, the images are imported in the JPEG format. Learn how to fix photo imports being auto converted from RAW to JPG.