This was mistaken as watermarked/copyrighted I believe. I would contact Hubpages and explain it to them that this is a program that you use that has given you free rights to your own pictures.
Anyone can flag your page. It is up to you to at least to refute it sense it is a mistake after all. I think they may be understanding. Example: someone flagged one of my pages for 6-7 broken links and not one was broken- I promise & I still have that page up and it's not flagged anymore. I hope this works out for you! :)