I assume that you want to do this from ASP.NET (as opposed to a WinForms application).
- System.Windows.Forms(, , ). System.Windows.Forms.WebBrowser:
WebBrowser browser = new WebBrowser();
browser.Navigate(@"http://www.stackoverflow.com");
, BitBlt API (, ), WebBrowser Bitmap ( ). WebBrowser Handle .
: - , , : http://www.developerfusion.com/code/4712/generate-an-image-of-a-web-page/