Prototype: Change attribute

How can I change a <img> with the JS-Library Prototype? I managed it to get the element but I couldn't change the "src":

$('item1').getEle开发者_StackOverflow社区mentsBySelector('img')

var imgs = $('item1').getElementsBySelector('img');
imgs.each(function(img) {
    img.src = 'newSrc';
});

You can also use the setAttribute function.

var imgs = $('item1').getElementsBySelector('img');
imgs.each(function(img) {
    img.setAttribute('src','newSrc');
    img.setAttribute('width','100px');
});