The following code example sets the ContentType property for the response to image/jpeg, calls the Clear method to remove other content that might be attached to the response, and then sets the BufferOutput property to true so that the entire page will be processed before any content is sent to the requesting client.
// Set the page's content type to JPEG files// and clear all response headers.
Response.ContentType = "image/jpeg";
// Buffer response so that page is sent// after processing is complete.
Response.BufferOutput = true;