How to convert my HTML Code to Image in asp.net c#

Consider the LEADTOOLS SDK (https://www.leadtools.com/downloads?category=main) which you can use to load a memory stream containing your HTML string then produce the desired appearance as an image.

The code to do this would look like this:

using (MemoryStream ms = new MemoryStream())
{
string HTMLString = " Test HTML .style1 { font-size: xx-large; }
Hello WebWorld!
";
StreamWriter writer = new StreamWriter(ms);
writer.Write(HTMLString);
writer.Flush();
ms.Position = 0;
RasterCodecs codecs = new RasterCodecs();
RasterImage image = codecs.Load(ms);
codecs.Save(image, "outfile.jpg", RasterImageFormat.Jpeg411, 0);
}

The Result will look like this: