Responsive images

Feature request: enable responsive images in articles.

Use case:

• Better response/load times for mobile users.
• We'd be able to serve custom, relevant visual content for a mobile breakpoint, when the user's device meets the breakpoint threshold. And serve content for a desktop breakpoint to desktop traffic.
• Improve page load times/responsiveness by serving smaller image files to mobile users (also conserving mobile data).
  
  

Impact of missing feature:

This is pretty important to us as around 2/3 of our traffic is on mobile. We have to choose between:

• Serving only desktop or mobile breakpoint images to all users. Many users see content that's not relevant to them. May confuse some users
• Serving both desktop and mobile breakpoint images to all users. Doubling the number of images needed per article, negative impact on page performance and mobile data use. May confuse some users.
  
  

Other info:

Google's got a guide for creating responsive images. I've tried this out in a test article, but the 'srcset' attribute isn't being retained in the source code editor. If the code editor allowed the 'srcset' attribute, that would be awesome!