function fp_img_init(){
	setInterval(fp_img_swap,5000);
}

function fp_img_swap(){
	fp_img_index++;
	if(fp_img_index>=fp_imgs.length) fp_img_index=0;
	
	var el=$("fp_img");
	var old_img=el.firstChild;
	var new_img=document.createElement('img');
	new_img.setAttribute('src',fp_img_prefix+fp_imgs[fp_img_index]+'.jpg');
	
	Element.setOpacity(new_img,0);
	el.appendChild(new_img);
	new Effect.Fade(new_img,{from:0,to:1,duration:2,afterFinish:function(){el.removeChild(el.firstChild);}});
	
}

Event.observe(window,"load",fp_img_init);