No, you do not need to enter a separate license for each cloned image.
The licensing of Windows Embedded works different than for normal Windows versions.
A image is fully licensed if you put a license sticker onto the device.
If you need more details you can contact us any time!
For more details on how to create a full version image for XPe/WES have a look at the “How to enter the product key in XP Embedded / Windows Embedded Standard?” post.
This is only valid for the following products: