According to my tests after a few weeks, it doesn't break any Netflix features, all actions/buttons (video loading, clicks on movie/next episode, ...) are still working as intended, only spoiler pictures are hidden.

Obviously english isn't my native language, so if you have a better description, don't hesitate to send it to me.
This is public licence so feel free to use this very short code to create/improve other userstyles/browser extensions.