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.
Logo Design Copyright: Do I own the copyright to my logo?
When you’ve a logo created by a graphic designer, who owns the copyright to that logo at the end of the process? Having created many, many logos in my 19 years of commercial design experience, I’d like to give you some advice that will stand you in good stead for any future interactions you may have between yourself and a logo designer.