external image as source

[WillyRamirez]

Hi, according to the docs the source provided to watermarkImages[] should be a local image.

So is using an external image unsupported? I am trying to currently add an external watermark image to a local image but it does not seem to work. The local image works fine and a local watermark also works.
Does anyone have a workaround for external images to be used as a watermark?