this is a Tampermonkey script for itunes.click album cover for download it as 1200x1200 resulotion.

tampermonkey-itunes-large-cover.js

// ==UserScript==
// @name       itunes Large Cover
// @namespace  https://github.com/larvata
// @version    0.1
// @description  click album cover for download it as 1200x1200 resulotion.
// @match      https://itunes.apple.com/*/album/*
// @copyright  2013+, Larvata
// ==/UserScript==

var artworks=document.getElementsByClassName('artwork');
for(var i=0;i<artworks.length;i++){
    var tImg=artworks[i];
    if(tImg.nodeName=='IMG'&&tImg.width==170&&tImg.height==170){
  	var tLink=artworks[i].parentNode.parentNode;
        tLink.href=tImg.src.replace('170x170','1200x1200');
        tLink.setAttribute('target','_blank');
        tLink.setAttribute('download',tImg.alt);
    }
}