UTTypeCreatePreferredIdentifierForTag() is used to get the image type from the mime type only on macOS. On iOS, utiFromImageBufferMIMEType() handles only three image formats manually: png, jpeg and gif. On macOS and with user created with "sysadminctl", UTTypeCreatePreferredIdentifierForTag() fails to return valid image type for the mime type "image/png".
rdar://107625991
Pull request: https://github.com/WebKit/WebKit/pull/14163