iphone – UIImagePickerControllerOriginalImage vs原始资产数

我正在使用imagePickerController,我已经确定我有2个选项

>使用UIImagePickerControllerOriginalImage中的UIImage
>使用UIImagePickerControllerReferenceURL获取原始资产
ALAssetsLibrary assetForURL(我不喜欢这个,因为它提示了
用户使用他们当前的位置,我不需要)

我的问题是……如果我使用第一个选项和第二个选项,图像的质量是否有任何差异？

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    //option 1
            UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
            NSData *imgData = UIImagePNGRepresentation(image);

    // option 2 (will prompt user to allow use of current location)
            NSURL *imgURL = [info objectForKey:@"UIImagePickerControllerReferenceURL"];
            __block NSData* imgData;

            ALAssetsLibrary *assetLibrary=[[ALAssetsLibrary alloc] init];

            [assetLibrary assetForURL:img resultBlock:^(ALAsset *asset)
             {
                 ALAssetRepresentation *rep = [asset defaultRepresentation];
                 Byte *buffer = (Byte*)malloc(rep.size);
                 NSUInteger buffered = [rep getBytes:buffer fromOffset:0.0 length:rep.size error:nil];
                 imgData = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES]; 
             }
                       failureBlock:^(NSError *err) {
                             NSLog(@"Error: %@",[err localizedDescription]);
                         }]; 
        }