stock.tookapic.com
It serves thousands of free images and free videos with public domain license CC0. All images are free for privat and commercial use.
shutterstock.com
A global marketplace for images, videos and music. You can search millions of royalty-free stock photos, illustrations and vectors.
istockphoto.com
iStock website has got for millions of exclusive, royalty-free stock files. You can find the perfect stock for your project.
streetwill.co
Free vintage photos to use any way you want.
LINK: http://streetwill.co/
freenaturestock.com
Free Nature Stock is a neat compilation of nature related images found on one website. These images may be suitable to use in your nature-themed social media posts. Since it is under the Creative Commons Zero, you are free to do whatever you want with their images.
albumarium.com
Albumarium offers a gallery of free and high-quality images to be used for your social media campaigns. You can sift through their galleries and sort through categories like animals, cities, people, nature, metro, and more. Images on this website use the Creative Commons Attribution 2.0 license.
LINK: http://albumarium.com/
imagebase.net
Imagebase is absolutely free stock photography, commercial, personal or educational.
LINK: http://imagebase.net/
getrefe.com
Refe is a marketplace of royalty-free, high-quality, natural looking photos of people interacting with technology. It has got also free option.
LINK: http://getrefe.com/
shotstash.com
Shot Stash is a source of royalty-free images that can be used for backgrounds or banners. Choose from several different categories to see what is right for your web project. Images may be used for personal or business purposes and do not need attribution.
LINK: https://shotstash.com/
graphicstock.com
GraphicStock provides unlimited downloads of royalty free stock images, vectors, illustrations, icons, buttons and other graphics of all kinds.