This is just a test for microservice.
Run docker build -t image-transformer . and then you will build a docker image width official node:latest and imagemagick:latest env.
I tried with docker 1.7, and there is no more test for other version.
Then run some code like this:
docker run -d -p 8081:8081 --name image-transformer -w /app -v "$(pwd)":/app -v image-transformer npm start
and you will get some image service from the server.js, if you want to get more about node with imagemagick, click here
The server.js and test folder are just tmp files for a test of the docker image