JSFiddle - React, Tailwind, and code Playground

by Colin

HTML

<img src="https://cogni.ca/so1.png"
     data-src-960px="https://cogni.ca/so2.png"
     data-src-1260px="https://cogni.ca/so3.png"
     alt="">

CSS

@media (min-width:320px) {
        img[data-src-960px] {
            content: attr(data-src-960px, url);
            outline: 1px solid orange;
        }
    }

    @media (min-width:960px) {
        img[data-src-1260px] {
            content: attr(data-src-1260px, url);
            outline: 1px solid red;
        }
    }