Cacher is the code snippet organizer for pro developers

// ==UserScript==
// @name        Slack Large Emoji
// @namespace   https://gist.github.com/tkrkt
// @include     https://*.slack.com/messages/*
// @version     1
// @grant       none
// ==/UserScript==

var style = document.createElement('style');
style.textContent = `
span.emoji {
    width: 128px;
    height: 128px;
}`;
document.head.appendChild(style);