I did not test this yet, but sounds intriguing. And the sample results look believable.
https://github.com/texturedesign/texturize?s=03
texturize

A command-line tool and Python library to automatically generate new textures similar to a source image or photograph. It's useful in the context of computer graphics if you want to make variations on a theme or expand the size of an existing texture.
This software is powered by deep learning technology — using a combination of convolution networks and example-based optimization to synthesize images. We're building texturize as the highest-quality open source library available!

https://github.com/texturedesign/texturize?s=03#2-commands
Full doc and examples on Github.
https://github.com/texturedesign/texturize?s=03
texturize

A command-line tool and Python library to automatically generate new textures similar to a source image or photograph. It's useful in the context of computer graphics if you want to make variations on a theme or expand the size of an existing texture.
This software is powered by deep learning technology — using a combination of convolution networks and example-based optimization to synthesize images. We're building texturize as the highest-quality open source library available!

https://github.com/texturedesign/texturize?s=03#2-commands
Full doc and examples on Github.