Change background of a DIV in iframe

Next Person,

I have a form to upload any image ...

<form id="form-upload" enctype="multipart/form-data" action="url" method="post">
    <input type="file" name="image" id="image" />
    <input type="submit" name="salvar" value="Salvar" />
<form>

I want to put the image that was sent as background of a div in an iframe, using ajax, so I do not need to refresh the page, I would like to know a way to do this, is it really necessary to upload the image? >

My JS code:

$('#form-upload').on('submit',function (e) {
    e.preventDefault();

    var formData = new FormData(this);

    $.ajax(
    {
        url: uma_url_qualquer,
        type: 'POST',
        data: formData,
        success: function (data) {
            console.log("sucesso");
        },
        cache: false,
        contentType: false,
        processData: false
    });
});