Image upload through ajax

// create model for controller
var model = new FormData();
model.append('Name', $.trim($contestForm.find('[name="nombre"]').val()) + ' ' + $.trim($contestForm.find('[name="apellido"]').val()));
model.append('Email', $.trim($contestForm.find('[name="email"]').val().toLowerCase()));
model.append('City', $.trim($contestForm.find('[name="cuidad"]').val()));
model.append('Title', $.trim($contestForm.find('[name="title"]').val()));
model.append('Description', $.trim($contestForm.find('[name="description"]').val()));
model.append('CountryCode', 'co');
model.append('Image', $contestForm.find('[name="file-es"]')[0].files[0]);  // this has the file for sure

$.ajax({
    url: '/Umbraco/api/ControllerName/CreateContestEntry',
    type: 'POST',
    dataType: 'json',
    data: model,
    processData: false,
    contentType: false,// not json
    complete: function (data) {
        var mediaId = $.parseJSON(data.responseText); //?

    },
    error: function (response) {
        console.log(response.responseText);
    }
});