These image tools will only take effect if you export an image. Here you can overlay a watermark to your images e.g. with your logo or copyright information.
To overlay your images with a watermark, select “Watermark” from the options in the “Export Objects As…” window. This opens the Watermark window.
In the right “Layer” area, click on any layer you want to edit. From the toolbar on top of the list you can add images or text to overlay, or you can remove the current selected layer. The current layer is highlighted in the list and the element is displayed with a frame on the image preview.
In the bottom properties area you can modify each single layer.
To build and save your own watermark settings you don't need to open the “Export Object As…” window. You simply can open the “Watermark” image tool from the Image Tools menu.
The selection in the image archive is used as sample images for the preview area.
Once you saved the watermark settings while being in the image archive, you can load and use them anytime you export images.