Hey, on 1.3.7 carrousel element has images as img with srcset, which is good to get the perfect size for diferents screens, as we talk here:
Now, on 1.4 RC2 carrousel element doesn´t has images with srcset, because now the img on html is a div with a background image.
I think is important to get the best web speed to go back and has the carrousel element from 1.3.7.
OK. I have the solution. Use adaptative height on carousel and srcset is there! Thanks to comment everything on the php, because it solve my question.
Thanks for your report!
I’m glad you found the adaptive height setting and that it solves your problem.