I see tons of websites offering renders.are you allowed to use those renders on a commercial website?
If it's an authorative site that offers this as a part of a free package and someone you could be sure that the site's designers created, then yes you are allowed to use them in commercial websites. Althought you may need to meet certain requirements or take permission from the site. If the site offering renders is one of those warez site that are filled with Template Monster templates, then am afraid No!