C# WebClient works from server but not client

[galan1971]

Hello, I'm trying to post to a page on a remote server and retrieve the
result page and all is working fine except for one thing, the images
which are dynamically created on the remote server appear broken. Here
is the code:

WebClient webClient = new WebClient();
webClient.Headers.Add("Content-Type",
"application/x-www-form-urlencoded");
byte[] response = webClient.UploadData(URL, "POST",
Encoding.GetEncoding("ISO-8859-1").GetBytes(PARAMETERS));
Response.OutputStream.Write(response, 0, response.Length);

1. This script is in a default.aspx file on my IIS server
2. If I open the path to that page in my browser on my laptop then the
images are not created and appear broken
3. If I open the path to that page in my browser on my IIS SERVER than
everything works fine

I have tried adding the line
webClient.Credentials = new System.Net.NetworkCredential(USER,PASS);
but that is not doing anything

Anybody have a clue