based markup for picturefill.
Outputs markup for use with the picturefill responsive images library by Scott Jehl, which allows you to specify a number of images to use at different media query breakpoints, as well as images for high-resolution displays.
This method accepts a number of shorthand argument keys to quickly output the necessary media query min-width, max-width, and min-device-pixel ratio media query declarations, as well as smart values for these keys to define either separate image files to use, or a resize operation on this image.
Note: MasterPress includes the picturefill.js and matchmedia.js libraries which can be enqueued with the following identifiers, anytime before wp_head().
wp_enqueue_script(‘mp-matchmedia’);
wp_enqueue_script(‘mp-picturefill’);