Redeploy .war in sun AS 8.1 without deleting existing files

[sri lakshmi]

I am using Netbeans 4.1 which is integrated with sun application server 8.1

I want to find out the strategy for redeploying the web application in the sun application server without deleting the existing files in the server.

The web application allows users to upload some image files through the browser. The uploaded images are stored under a directory called "userimages" parellel to WEB-INF.

The problem is that everytime I redeploy the project in the server, it deletes the existing files in the server and creates new files from the .war. I loose all the files that are uploaded by the users.
I would like to know what steps I should follow to retain the files in the server while redeploying.

Thanks a lot.