There are some very similar looking images on this website under http://diowonderland.com/category/graphics/textures/, which might need some explanation.
Those pictures are screenshots of textures applied to a 3D environment. The original images i create are squares with seamless edges, like the example you see below.
The squares are seamless, so they can be merged without any visible gaps.
Added to the surface of some 3D models within a suitable program you get a textured environment like those you see in the screenshots. Within some engines you can also add effects, like the reflection on this marble texture.
- I use Unreal Engine 4 to create the 3D surroundings. (Game engine, free to use.)