Tictail - Image src resize in mobile

resize.js

// # Tictail Product Image resize
//
// Use on themes that dont use the "mobile optimized layout" feature on tictail. 
// The code resizes the products <img src=""> to lower resolution images.

// When document is ready preform the following actions:
//
$(function () {
  if (window.matchMedia("(max-width:768px)").matches) {
    $('.lazy').attr('data-original',function(i,e){
      return e.replace("size=500","size=300");
    });
  }
});