var buttons = {
	'button-go' : {
		'normal' : '/images/button-go.png',
		'hover'  : '/images/button-go-hover.png'
	},
	'button-signup' : {
		'normal' : '/images/button-signup.png',
		'hover' : '/images/button-signup-hover.png'
	},
	'button-readmore' : {
		'normal' : '/images/button-readmore.png',
		'hover' : '/images/button-readmore-hover.png'
	}
};

function update_image(element, ident, hover)
{
	if (hover)
		element.setAttribute('src', buttons[ident]['hover']);
	else
		element.setAttribute('src', buttons[ident]['normal']);
}