From "Deployment Solution 7.x: Image Storage, Replication, & Removal"
"the images are captured on the site server to which the client is connected for Task Services (when in automation, NOT when in production) into the deployment share under Task Handlers\Images":
http://www.symantec.com/docs/HOWTO21731
So if you can get the automation client to connect to another Task Server running the Deployment Server Task Handlers it will create the image there.