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However, it’s a good best practice and in good taste to do so whenever possible. The photographer or graphic artist is the one who must be credited, not the RGB Stock website itself, as RGB is simply the host of the images. If you are not sure of your rights as it pertains to a image that you want to use, RGB easily lets you contact the photographer or graphic artist for clarity.
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Summary: Pexels is a 100% free stock photo site. All photos on Pexels are licensed under the Creative Commons Zero (CC0) license; This means you can copy, modify, distribute and perform the photos without any restrictions. The pictures are free for personal and for commercial use, all without asking for permission or setting a link to the source. Every week, Pexels adds at least 70 new high resolution photos, which are hand-picked from free image sources.
They ensure that all images published on their site are all high-quality and licensed under CC0. Only creative commons photos from reliable sources like Unsplash, Gratisography, Little Visuals and many more are added to their photo database.