The thumbnails are generated using phantomjs server. I'm using https://github.com/blockai/phantom-pool to make sure the phantomjs instance is reused. Also I'm using a scheduling node package (https://github.com/Automattic/kue) to make sure that images are precached as the link are submited to hackernews.

I'll post the code on https://github.com/valentinvieriu/vue-hackernews-2.0, but need to take care of some hardcoded redis credentials first. I'll give a reply when it's up