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How to render a PNG at higher resolution in C#

We would like to use GroupDocs Converter to create thumbnail image of various document formats, but the output quality is rather bad.
Please see the huge difference between the output from the Viewer and Converter:
Thumbnail Conversion.png (3.7 KB)
Thumbnail Viewer.png (16.6 KB)

For the viewer those options were used:

                var options = new ViewOpts.PngViewOptions(pageStreamHandler.CreateNewStream)
                    Width = 256 //pixel -> low resolution for thumbnails
                viewer.View(options, 1);

For conversion those options were used:

            var options = new ImageConvertOptions()
                Format = ImageFileType.Png,
                //convert only the first page for thumbnail
                PageNumber = 1,
                PagesCount = 1,                    
                Width = 256 //pixel -> low resolution for thumbnail

I tried different options but I could not get better results with Conversion.
Is there some way to improve the quality that I overlooked?

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We could reproduce this issue and it’s been logged in our internal issue tracking system with ID CONVERSIONNET-4022 for further investigation and resolution. You’ll be notified as there’s any update.

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The issues you have found earlier (filed as CONVERSIONNET-4022) have been fixed in this update. This message was posted using Bugs notification tool by atirtahir3