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Introduction

The ASPX page noted below will extract an image from a database and display it on a web page. At not time will the file be saved to disk. The image in this example is extracted from a BLOB holding a GIF image. This example uses the Logo table located in the pubs database. This database is provided with Microsoft SQL Server 2000 as sample data.

This article is based on MSDN Article ID: Q173308. HOWTO: Display Images Stored in a BLOB Field

Getting started

The following code should be placed in an file called DisplayImage.ASPX.

<%@ Page LANGUAGE="c#" Debug="true" ContentType="image/gif"%>
<%@ Import namespace="System.Data" %>
<%@ Import namespace="System.Data.SqlClient" %>
<%
// Set the inital type of image (image/jpeg or image/gif) or (text/html)
try
{
	// Open database
	SqlConnection dbConn = new SqlConnection("data source=localhost;initial catalog=pubs;integrated security=SSPI;");
	//SqlConnection dbConn = new SqlConnection("data source=localhost;initial catalog=pubs;UID=sa;PWD=;");
	string sImageID = Request.Params["ImageID"];
	string sSqlQuery = "SELECT Logo FROM pub_info WHERE pub_id='" + sImageID + "'";
	SqlDataAdapter da = new SqlDataAdapter( sSqlQuery,dbConn); 

	// Load into memory
	DataSet ds = new DataSet();
	da.Fill( ds );
	
	// Check for data
	if( ds.Tables[0].Rows.Count > 0 )
	{
		// Output the data to the 
		Response.BinaryWrite( ds.Tables[0].Rows[0][0] as byte [] );
	}
	else
	{
		// No Database match found
		Response.ContentType = "text/html";
		Response.Write("<b>Image not found!</b><br>");
		Response.Write("Expected format http://..../DisplayImage.aspx?ImageID=0877<br>");
		Response.Write("Recieved ImageID =" +  sImageID + "<br>");
	}
}
catch( Exception ex )
{
	Response.ContentType = "text/html";
	Response.Write("<b>Read failed due to excepetion!</b><br>");
	Response.Write(ex.ToString());
}
Response.End();
%>

Recalling the image on its own page

The images can be extracted in one of two ways. The first is to call the page directly from the Internet Explorer Address bar. The line for this should read as follows;

http://..../DisplayImage.aspx?ImageID=0877

This will display image with an ID of 0877. Using this methods is handy when you are testing to code and need to display the messages that indicate error conditions.

Inserting the image into a web page

This second method displays the image on the web page an a normal image would appear. The following HTML is inserted directly into the page to display the image.

<IMG SRC="DisplayImage.ASPX?ImageID=9999">

Note here the image to be display is the one with ID of 9999.