As of 1.7.0, we have included a watermarking feature. However, we still don't think you should use it.
Nope, we do not have an automatic watermarking feature in Sunshine. And it has purposefully been left out. Here is why:
One of the biggest complaints we had with other photo carts which you installed on your own web server was the images clients looked at always had some kind of color distortion to it. Highlights were blown out, faces looked unnatural or colors were just plain off. The cause was the web server taking an original image to make a smaller version of it and adding a watermark image on top. It simply did not know how to handle advanced or custom color profiles and would often get colors plain wrong. Hours upon hours upon hours of researching, trying to save images in specific ways, fighting with the hosting company on settings of the image processor and ultimately images still never looked any better.
Having the best representation of how prints would actually look when the client received them was of the utmost importance to us. So this was a huge issue and one of the driving forces behind the decision to start Sunshine.
With Sunshine, we do create the thumbnail image on a gallery page dynamically via the server. However, click to an individual image and that is not server processed - that is the image you have uploaded via FTP. The result means you have significantly greater control over the quality of that image and what your client sees.
If you want to add a watermark to the image, you can absolutely do so via a simple batch process from Photoshop which will maintain the high quality you want to show your clients that a web server cannot match. We plan on putting out a tutorial on how to add a watermark and maybe even a simple action to run for your images. Stay tuned.
Also, this does not mean we will never build this feature in for those who are OK with the web server quality. But for 1.0 this feature is not available.