Even if you have copying/saving disabled on your website, all the person has to do is take a screen shot. It’ll be a low quality photo, but they could still use it online. With a watermark, all they have to do is crop it out if it’s on the edge. A huge watermark across the middle of the photo is likely to get you a spot on this website. There’s no real way to keep people from stealing your photos. Just take it as a compliment, but call them on it if they’re claiming the work to be their own.
And no, I haven’t looked at your website. I can’t get it to pull up.