Yes, you can upload documents, but there are copyright issues, so you need to either own the document or have permission to upload it. I haven't really tried asking for permission and instead give the information on where it comes from and if possible add a link to an online location where it can be found. That's why I source most gravestones from Find A Grave, and use the URL rather than a copy of the .jpg. That way you just need one click and you have the gravestone. BTW, you shouldn't really use FAG pages without a gravestone as sources since they normally don't have source for the information, and if they do, you're better off to go to where they found it and link to that site.
