You would need to collect and upload additional watermarks and headers for these categories. The main header in global options is shown over the gallery everywhere. However when you create a category for say the person you talk about you can specify an alternate header and watermark via server path to those files in Admin => Edit Categories for each cat.
The upload from url is where you would place a url to a page and we will attempt to extract images from that page in img html tags
The users upload directory is their own specific uploads directory and changes with user. Now you can upload from any folder on the server using bulkupload and changing the path as admin
Let me know if you need anything else.