How to image a thin client?

Our company has Dell WYSE thin clients (Windows Embedded Standard 7), and I have one configured the way I would like.  I am able to successfully load the PXE image and obtain an IP, but when I try to run a basic Upload Image task, it fails after several seconds with a Return code of 1.

For the Upload Image settings, it is using:

RapiDeploy

Image Type: Disk Image

Max file size: 2 GB

Compression:  Balanced for size/speed.

These thin clients have an 8GB disk split into two partitions (C and E).  I am not sure what it preventing the image from being uploaded.