2.Pexels: The pictures provided by this website are of very high quality and many kinds, including nature, cities, people, science and technology, etc.
3.Pixabay: the pictures provided by this website are free and can be used for commercial purposes. Picture types include photos, illustrations, vector diagrams, etc.
4.Freepik: The pictures and vector pictures provided by this website are free and can be used for commercial purposes. Pictures include illustrations, icons, backgrounds, etc.
5.Shutterstock: The pictures provided by this website are of very high quality, but they need to be paid. Picture types include photos, illustrations, vector diagrams, etc.
6.GettyImages: The pictures provided by this website are of very high quality, but they need to be paid. Picture types include photos, illustrations, vector diagrams, etc.
7.AdobeStock: The pictures provided by this website are of very high quality, but they need to be paid. Picture types include photos, illustrations, vector diagrams, etc.
8.500px: The quality of this website is very high, but it needs to be paid. Picture types include photos, illustrations, vector diagrams, etc.
9.Flickr: The picture quality provided by this website is uneven, but there are many high-quality pictures shared by users.
10.Picjumbo: The pictures provided by this website are of very high quality and can be used for free. Picture types include photos, illustrations, vector diagrams, etc.