Windows2003 website authentication PopUP

[Dig]

Hi,

Am running Windows 2003 server with multiple websites. On many of the webistes am getting windows authentication box, though the authentication box is not harmful but this should not happen.
Also, the popup comes somewhere middle of website while browsing.
mainly i have noticed while downloading the images on websites.
The HTTP 401 error

HTTP error codes
401"; Unauthorized
1- Logon failed
2- Logon failed due to server configuration
3- Unauthorized due to ACL on resource
4- Authorization failed by filter
5- Authorization failed by ISAPI/CGI application

As per the log of 401 error

2004-11-09 10:26:37 GET /incfiles/resize.asp path=../SiteImages/SubCatImage/FGSW-2402RS.jpg&width=65&Height=65 80 - 217.173.106.114 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.1) 401 1 0

some times just before the 401 error /incfiles/resize.asp this file was called.

most of times we are geting the while downloading the images. is it posible that while using aspjpeg it is resizeing the actual imagesize it does not get the iuser permission?

we are using aspjpeg with few sites only. but the authentication box is comming on nomal websites while downloading the images in a slow internet connections.

Any Help?

-dig