Trainspotting: Firefox 38
There is one caveat for Firefox 38 – responsive images willload using the correct media queries, but presently do not respond to viewport resizing. This bug is being actively worked on and tracked here, and will be fixed in a near-future version of Firefox.
With the release of Firefox 38 this week we now have <picture> and srcset available. There is one caveat: the images are based on the viewport when the page loads and won’t recalculate and request another image if the viewport resizes, a bug currently being worked on.
An excerpt from Trainspotting: Firefox 38
