NextGen – remove/edit watermark

Is there a way to remove the watermarks from images in a gallery?

I had set the watermarks, then attempted to change, but rather than replace the existing watermark, NextGen layered the new watermark on top of the previous.

I’ve flipped an image, so now the watermark on that image is backwards.

Please advise.
Thanks

https://www.ads-software.com/plugins/nextgen-gallery/