Textures.com - Textures.com is a website that offers digital pictures of all sorts of materials.

Img.vision - Image hosting & video hosting for eCommerce sellers

Poly Haven - Poly Haven (formerly known as Texture Haven) is an online website where you will find scanned textures without any cost and that are of high quality.

BeeIMG - BeeIMG is a simple, fast, easy image sharing solution created to fill up your image sharing needs.

Poliigon - A library of materials, and HDR's for artists including free textures that want photorealism.

ImageVenue - ImageVenue is a great online hosting service that allows uploading pictures for showing creative works with a simple-to-use technique.