Y'know, there's this really cool library in .NET for dynamically creating images on the fly. However, this article has nothing to do with that, so if that's what you're looking for, stop now. What this article is about is very simple -- how to use a single line of code (via a component call) to output the contents of an image residing on the server's hard drive. Why not just use an IMG tag? Well, we want this page to used as the SRC of an IMG tag, so it has to actually have a content-type of "image/gif" and use BinaryWrite to display the image. To do this in Classic ASP requires a custom component (or a third party component such as Persits ASPUpload, which has a SendBinary method that does this). In fact, let's take a look at how this works with a quick sample before we do it in .NET. Below is the complete code required to display a static image using ASPUpload. You can see this file in action by clicking here.

displayimage.asp:
1 <% OPTION EXPLICIT %>
2 <object id="objUpload" runat="server" progid="Persits.Upload.1"></object>
3 <%
4 objUpload.SendBinary Server.MapPath("/images/aspalliance_fade_468x60.gif"), True
5 %>

Now, let's do this in .NET. We can use the System.Drawing library to open an image and display it, using the following code:

displayimage.aspx:
1 <%@ Page language="c#" AutoEventWireup="false" Trace="false" Debug="false" %>
2 <% @Import Namespace="System.Drawing" %>
3 <% @Import Namespace="System.IO" %>
4 <% @Import Namespace="System.Drawing.Imaging" %>
5 <%@ OutputCache Duration="100" VaryByParam="none" %>
6 <%
7 string path;
8 path = Server.MapPath("///images//aspalliance_fade_468x60.gif");
9 System.Drawing.Image myImage = System.Drawing.Image.FromFile(path);
10
11 MemoryStream tempStream = new MemoryStream();
12 myImage.Save(tempStream,ImageFormat.Gif);
13
14 Response.ClearContent();
15 Response.ContentType = "image/gif";
16 Response.BinaryWrite(tempStream.ToArray());
17 Response.End();
18 %>

Here is the result of using this code as the SRC of an IMG tag:


Old:(Notice that there is a problem here -- this is an animated GIF, but this version doesn't show any more than the first frame of the graphic. Not good. So we'll scrap that version, hope that perhaps there is an animated GIF type supported in the future, and move on.)

As you can see, the above example renders the animated GIF image just fine now, thanks to updates to the .NET Framework in Beta2. The HTTPImage Class, below, is no longer necessary, but is left for posterity. -- Steve The HTTPImage Class -- NO LONGER FUNCTIONAL (or necessary) UNDER BETA 2

You can tell we're getting to the real thing now, because I actually bothered to put the working code into a class file. In this case, I called it HTTPImage, and it's written in C# and has two simple methods. Actually, one overloaded method, outputImageViaHTTP, which takes either a virtual file path or a static file path. Before we get into the class, let's see it in action by looking at a simple ASPX page that uses it. Click here for the example, and below is the source code. Note that the ASP.NET page is passing its own instances of Response and Server to the component (line 8). We'll see how the component uses these below.

displayimage2.aspx:
1 <%@ Page Language="c#" ContentType="image/gif" %>
2 <%@ Import Namespace="stevenator.components" %>
3 <%@ OutputCache Duration="100" VaryByParam="none" %>
4 <script language="c#" runat="server">
5 protected void Page_Load(object sender, EventArgs e)
6 {
7 HTTPImage myHTTPImage = new HTTPImage();
8 myHTTPImage.outputImageViaHTTP("//images//aspalliance_fade_468x60.gif", this.Response, this.Server);
9 }
10 </script>

Pretty cool, eh? The image is actually animated, as it's supposed to be. Now, the reason