Step #1
Chrome:
1- Install Tampermonkey https://chrome.google.com/webstore/detail/tampermonkey/dhdgffkkebhmkfjojejmpbldmpobfkfo?hl=en

OPERA:
1- Install Tampermonkey https://addons.opera.com/en/extensions/details/tampermonkey-beta/

FIREFOX
1- Install Violentmonkey https://addons.mozilla.org/en-US/firefox/addon/violentmonkey/

SAFARI (Untested)
1- Install UserScripts from the mac app store https://apps.apple.com/us/app/userscripts/id1463298887

Step #2 install this script into that plugin

// ==UserScript==
// @name         AstolfoPlace
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  astolfo outline
// @author       oralekin
// @match        https://hot-potato.reddit.com/embed*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=reddit.com
// @grant        none
// ==/UserScript==
if (window.top !== window.self) {
    window.addEventListener('load', () => {
            document.getElementsByTagName("mona-lisa-embed")[0].shadowRoot.children[0].getElementsByTagName("mona-lisa-canvas")[0].shadowRoot.children[0].appendChild(
        (function () {
            const i = document.createElement("img");
            i.src = "https://cdn.discordapp.com/attachments/926482574640054333/960174646588747846/astolfo2.png"
            i.style = "position: absolute;left: 0;top: 0;image-rendering: pixelated;width: 1000px;height: 1000px;";
            console.log(i);
            return i;
        })())

    }, false);

}