Koru lets you add watermark to the scene you make, but it takes it to another level with its 2D image nodes that work as overlays.
Let's start with a simple scene and select an image to become the watermark. I'll use the built-in one from the materials panel for this tutorial:
Drag and drop the image into the scene and select "Create Watermark" in the popup menu:
You see the image is placed to the screen, not to the scene or object. This is a 2D image node that you can see in the scene tree and edit in node properties panel:
When an image node is selected, you see its gizmo that you can use to move, rotate or scale the image. It snaps to round angles, margins and scales but you can hold Shift to avoid this.
You can also edit the parameters directly using the scene properties panel. Here's the list of the image node properties there:
Image nodes are aligned to the screen/preview area, so plan your layout according to that.
You may have as many image nodes as you want.
Best of all, image nodes (like any other nodes) are affected by snapshots. This means you can move, rotate, scale, show and hide them using snapshots.
This way you can create captions, titles, extra backgrounds for animations and so on, or simply move the watermark to a better location for that specific angle of view.
Great, you've just learnt another Koru trick. The main thing is that watermarks are not just watermarks, they are actually first-class node objects living in screen space.