[scaturr]

Well what if you batch it in the browser? It is quite possible to use file inputs to generate watermarked images without ever storing the image you are watermarking, and then upload the result.

[nathankleyn]

Yep - that's totally possible. Actually, now you phrase it like that, I see what you mean about using it that way for a CMS, and it's an awesome idea.

[artursapek]

You could also use the canvas element to display the image & watermark as a flat layer.

[kuschku]

Still, the image would somehow have to be loaded in the browsers, at which point it’s easy to circumvent.