Blurb doesn't review, edit, or monitor books and Wall Art as they come through, and we can't advise on whether it's legal or "safe" for you to use content you've found on the internet or elsewhere. Using copyrighted material without the right to do so violates our Terms and Conditions.
If you're looking for photos or other content for your project, some artists make their content available for re-use through Creative Commons licenses and similar programs. Public domain material may be available as well. There may be restrictions involved, so it's always wise to confirm the license and exact terms of use for any content you wish to use.
The World Intellectual Property Organization also has some excellent FAQs on copyrighted material under the Using other people's work section.
Remember, the content is entirely up to you, the author. We don't review, edit or monitor content and we will investigate any complaints of copyright infringement.