When a chart is rendered using binary streaming, two web pages are used: one page that creates the Chart control and another that makes reference to the page with the Chart control. 

The page that that creates the Chart control is a simple ASPX page, and the Chart control's rendering method is set to BinaryStreaming. On this page, all HTML tags are removed, leaving only the Chart definition in XML. You can still use code-behind.

The second page that makes reference can be any webpage, including HTML and ASP, and contains an IMG tag with its SRC attribute set to the name of the first page. For example, <img src='UsingWithLegacyImage.aspx'>.  This rendering method is fast because it does not require any disk space or security rights for writing data to the temporary image files.

This sample uses a webform and a legacy HTML page:

#1 - UsingWithLegacyImage.aspx - contains the Chart control.
#2 - UsingWithILegacy.htm - contains the image tag.