Asp.net(c#) code to convert html content to an image

Question

http://www.c-sharpcorner.com/UploadFile/0c1bb2/capture-screen-shots-of-page-using-Asp-Net-C-Sharp-without-script/

 

I tried that above link, but it take screenschot as usual whole page.

 

So i need to take Image as per specify html id(div.form,body).

 

Thanking U.....