message: Adds alt tags to home page images
diff: a.Button.Button--size-lg.Button--app.Button--border-heavy( class=button_class href=sd.ITUNES_LINK )
  | Download Are.na for iOS
  .HomeHero__image.js-to-fold.pointer
  - img(src="https://d2w9rnfcy7mm78.cloudfront.net/1823396/original_a478a524577ed32227e7b36894cbb04a.png")
  + img(src="https://d2w9rnfcy7mm78.cloudfront.net/1823396/original_a478a524577ed32227e7b36894cbb04a.png" alt="Are.na screenshot")
  