gistfile1.js

[…]

forms.item(1).on(
	'submit',
	function(e)
	{
		e.preventDefault();
		this._upload(e.target)
	},
	this
);

[…]

_upload: function(form)
{
	Y.io(
		Y.config.api+'images/upload',
		{
			method: 'POST',
			form: {
				id: form,
				upload: true
			},
			on: {
				complete: function(id, data)
				{
					console.debug(data);
					
				}
			},
			context: this
		}
	);
}

[…]