Multiple Watermarks

Hello. Maybe I’m just missing something, but I didn’t see my issue addressed. I can’t seem to create a second image-based watermark. I have a primary image watermark and would like to create a variation of the same for use on darker photos, but I can only add a text-based second watermark. It does not allow me to select image or upload an image. Is this a limitation of the free plugin, or am I missing something? Thank you.