Ideas Portal
At this time it seems like you can only pull in TEXT data from site user and custom fields in Pressero. We share URLs of headshots and logo images and would like to be able to use these for a preview of the print or merchandise items. You allow of uploads, why not allow a hosted URL image to allow be used?
This can be done to a certain extent using site user Assets in Pressero. If a user has access to any assets on the Pressero site, then they can be available on upload image fields in eDocBuilder, FYI.
Assets
You can also feed images into an image field from URL addresses input in the template.
Example Template
In that case, there is a dropdown field for input where a label is chosen, and then there is scripting on the field that returns a url directly to an image in the Pressero account, but it could be any url.
Field Scripting Example
Neither of those is really what you mean, if I am reading your comment correctly, and there should be an easier way. But if you want to take a closer look at how that functionality works, please open a ticket to us at support.aleyant.com and one of us can webinar with you for a bit to look over it.