AccessViolationException error

            var image = new PsdReader(sourceFileName);
            for (int i = 1; i < image.Frames.Count; i++)
            {
                try
                {
                    var layer = image.Frames[i];
                    if (layer.Type == FrameType.Group)
                    {
                        continue;
                    }
                    using (var bitmap = layer.GetBitmap()) //There's going to be a mistake.
                    {
                        var ms = new MemoryStream();
                        bitmap.Save(ms, new PngSettings());
                        var image2 = Image.FromStream(ms);
                        image2.Save(dataDir + "testimg\\" + i + ".png");
                    }
                }
                catch (Exception e)
                {
                    continue;
                }
            }