How to add signature to uploaded images?

[Heliosurge (Dan DeMontmorency)]

There is this as an option

Discourse Web Page Watermark

This theme component adds a watermark to the page. It is possible to add any of the following information: a short text message the username currently logged in the timestamp the page was rendered Several settings allow customizing how and when the watermark will be rendered: show_watermark_in_background: If enabled will generate and display a watermark on the page. scroll_enabled: If enabled the watermark will be scrolled with the page. only_in_categories: List of categories in whi…

And this can be used in more of a manual idea

Image Annotator - Allows you to annotate images in the previewer

I’m thinking this could be used to automatically watermark photos by username, but I’m not sure how to go about that. Perhaps another button that prints [username]@[site domain]?