Can I use watermarked images?
If you use a watermarked image on any of your marketing materials, digital or print, without written permission from the rights holder then you are infringing the copyright of that watermarked image.
How do photographers protect their images?
Once you register an image, you'll receive a certificate that clearly proves you are the rightful copyright holder. It's simple enough to get a copyright certificate: Traditionally, any photographer could always go to a site like copyright.gov to protect their images.