You can write a handler that opens the file on the network and writes its contents to the response. then you can set the image url using that handler as below
<asp:image runat="server" imageurl="~/NetworkImageHandler.ashx?file=file.jpg" xmlns:asp="#unknown" />
and sample handler code
<![CDATA[<%@ WebHandler Language="C#" Class="Handler" %>]]>
using System.IO;
public class NetworkImageHandler : System.Web.IHttpHandler
{
private const string NETWORK_SHARE = @"\\computer\share\";
public void ProcessRequest(HttpContext context)
{
string fileName = context.Request.QueryString["file"];
string path = Path.Combine(NETWORK_SHARE, fileName);
context.Response.ContentType = "image/jpg";
context.Response.WriteFile(path, true);
}
public bool IsReusable { get { return false; } }
}
Reference:
http://stackoverflow.com/a/23693948/2558060[
^]
http://aspalliance.com/1322_Displaying_Images_in_ASPNET_Using_HttpHandlers.5[
^]
http://bytes.com/topic/asp-net/answers/884578-image1-imageurl-not-rendering-image-when-retrieving-different-directory[
^]