Dockerized PhantomJS 1.9.7, and 2.2.0-dev running on Alpine Linux
The size of the image is just about 80MB, because it contains only the dependencies of PhantomJS. The 2.2.0 is also UPX-ed, so this is why can be small, start time is also much better.
Test if it works:
docker run pickapp/phantomjs:1.9.7 -v
docker run pickapp/phantomjs:2.2.0-dev -v