Clone this repo and create a responsive image gallery using the gallery.json file for data. Include and/or create what ever other resources you may need then submit a pull request.
Make sure to document your decision process in your code and elaborate on challenges and solutions in your commit messages and pull requests.
Keep in mind, this is more about problem solving rather than strictly skill with code. Highlight areas you are strong in, but don't sweat any weaker areas too much.