IOS 相册高清图片加载

调用[[asset defaultRepresentation] fullScreenImage] 加载的是高清图片调用[asset thumbnail] 加载的是缩略图片调用asset.aspectRatioThumbnail加载的是较高清图片CGImageRef thumbnailImageRef = [[asset defaultRepresentation] fullScreenImage];UIImage *thumbnail = [UIImage imageWithCGImage:thumbnailImageRef];