picture srcset

<picture>
    <!--- Small Screens  --->
    <source srcset="http://placehold.it/767x767" alt="some alt text" media="max-width(767px)">
    <!--- Medium screens --->
    <source srcset="http://placehold.it/1024x1024" alt="some alt text" media="min-width(768px)">
    <!--- Large screens --->
    <source srcset="http://placehold.it/1200x1200" alt="some alt text" media="min-width(1024px)">
    <!--- Fallback for browsers without support --->
    <img src="http://placehold.it/1200x1200" alt="Some alt text">
</picture>