解决从数据库中读取的保存图片再保存时出错的问题。

Former-commit-id: ed64e939fd8f7e9e8b0638a23dec427e1754a001

labs/CameraCard/CameraCard/Infrastructure/ImageHelper.cs

@@ -36,16 +36,19 @@ public static class ImageHelper
     public static string ToBase64(this Image image)
     {
         var info = ImageCodecInfo.GetImageEncoders().First(o => o.FormatID == ImageFormat.Jpeg.Guid);
-        using (var encoderParams = new EncoderParameters(1))
+        using (var image2 = new Bitmap(image))
         {
-            using (var param = new EncoderParameter(Encoder.Quality, 70L))
+            using (var encoderParams = new EncoderParameters(1))
             {
-                encoderParams.Param[0] = param;
-                image.Save("temp.jpg", info, encoderParams);
-                using (var ms = new MemoryStream())
+                using (var param = new EncoderParameter(Encoder.Quality, 70L))
                 {
-                    image.Save(ms, info, encoderParams);
-                    return Convert.ToBase64String(ms.ToArray());
+                    encoderParams.Param[0] = param;
+                    image2.Save("temp.jpg", info, encoderParams);
+                    using (var ms = new MemoryStream())
+                    {
+                        image2.Save(ms, info, encoderParams);
+                        return Convert.ToBase64String(ms.ToArray());
+                    }
                 }
             }
         }