With a mobile-first responsive design approach, if any part of the process breaks down, your user can still receive a representative image and avoid an unnecessarily large request on a device that may have limited bandwidth. But with several newer browsers implementing an “image prefetching” feature that allows images to be fetched before parsing the document’s body, some of the web’s brightest developers are abandoning responsive images in favor of user agent detection, at least as a temporary solution. For us standardistas, UA detection leaves a bad taste in the mouth. More importantly, as the number and kinds of devices continue to grow, UA detection will quickly become untenable—just as browser detection did back in the bad old days before web standards. What’s really needed, argues Mat Marquis, is a new markup element that works the way the HTML5 video element works. Sound crazy? So crazy it just might work.