为什么使用 UIImageJPEGRepresentation 和通过 localpath 获取图像之间相同图像的数据大小/长度不同

    - (void)imagePickerController:(TZImagePickerController *)picker           
       didFinishPickingPhotoModes:(NSArray<RHPhotoModel *> *)photos  
                     sourceAssets:(NSArray *)assets           
            isSelectOriginalPhoto:(BOOL)isSelectOriginalPhoto      
                        infoArray:(NSArray *)infoArray {

            for (RHPhotoModel *model in photos) {
               UIImage *tmpImage = [UIImage imageWithContentsOfFile:model.photoPath];
               NSData *data1  = UIImageJPEGRepresentation(tmpImage,1);

               NSData *data2 = [NSData dataWithContentsOfFile:model.photoPath];

               UIImage *image = [UIImage imageWithData:data2];
               NSData *data3  = UIImageJPEGRepresentation(image,1);

               NSLog(@"data1=%lu, data2=%lu, data3=%lu", (unsigned long)data1.length, (unsigned long)data2.length, (unsigned long)data3.length);
        }

     [self dismissViewControllerAnimated:YES completion:nil];
 }

使用上述方法完成返回包含图像 photoPath 的 PhotoModel；
为什么我使用 [NSData dataWithContentsOfFile:model.photoPath];
data2 是 2497519 字节；
但是，我使用 UIImage *tmpImage = [UIImage imageWithContentsOfFile:model.photoPath]; NSData *data1 = UIImageJPEGRepresentation(tmpImage,1); data1 是 7234468 字节；

NSLog 数据：data1 = 7234468（字节），data2 = 2497519（字节），data3 = 7234468（字节）

在此处输入图片说明