GBF – Replace Home Image

// ==UserScript==
// @name         GBF – Replace Home Image
// @author       ~
// @namespace    ~
// @version      v1.0.0
// @description  Replaces home image with Glorybringer Djeeta
// @match        http://game.granbluefantasy.jp/
// ==/UserScript==

var stylesheet = `
.img-myimage{
    background-image: url("http://game-a1.granbluefantasy.jp/assets_en/img/sp/assets/leader/my/230301_sw_1_01.png");
    box-sizing: border-box;
    padding-left: 320px;
    background-size: 100%;
}`;

// injectStylesheet inserts `stylesheet` to the page
function injectStylesheet(stylesheet) {
    var stylesheetEl = document.createElement('style');
    stylesheetEl.innerHTML = stylesheet;
    document.body.appendChild(stylesheetEl);
}

injectStylesheet(stylesheet);