Can a cardholder upload a photo and NOT their Government ID (supporting docs)?

Yes this is possible, although it will not submit to the card office yet. As you can see below the photo without a supporting doc is "en route" and can only be accessed in the people tab under their provisioned account:

The cardholder will also get an email to remind them to complete the process:

How this works:

While we know that your card office may require supporting documents with the ID card photo submission, every step that the cardholder takes in the online photo submission process is saved - whether or not they are completely done with the process. The application is designed that way so that the cardholder can come back into CloudCard to finish the process at any time, without having to resubmit their photo and/or any supporting documents.