Disable asset fingerprinting

I am trying to disable asset fingerprinting by placing the following line in my config/environments/production.rb:

  config.assets.digest = false

However, rails isn't honoring this and still compiling assets with a fingerprint in public/assets/:

bear-e1d6322cce5569e1c88e51d726af8f49.jpg

Why is rails ignoring this? Follow up question: if rails is stubborn about fingerprinting assets, why won't it change the name of the asset in the html.erb file so that the browser will know the right name of the file to request?