function gE( obj_id ){
	return document.getElementById(obj_id);
}
function change_images( addr, side, now_id) {
	var img1_a = gE('img_pre0_a');
	var img2_a = gE('img_pre1_a');
	var img3_a = gE('img_pre2_a');
	var link1 = gE('link1');
	var link2 = gE('link2');
	
	if (side == "right") {
		write_position = now_id + 1;
		if (position[write_position])
			if (write_position+1 >= position.length-1)
				return false;
	}
	else {
		write_position = now_id - 1;
			if (write_position < 0)
				return false;
  }
 
    var a1a = addr+'/_photos/s_'+position[write_position];
    var a1b = addr+'/_photos/m_'+position[write_position];
    var a1c = addr+'/_photos/'+position[write_position];
    img1_a.innerHTML= '<img style="cursor:pointer" src="'+a1a+'" onclick="document.getElementById(\'full_img\').src=\''+a1b+'\'; document.getElementById(\'full_img_a\').href=\''+a1c+'\'" id="img_pre0">';
    var a1a = addr+'/_photos/s_'+position[write_position+1];
    var a1b = addr+'/_photos/m_'+position[write_position+1];
    var a1c = addr+'/_photos/'+position[write_position+1];
    img2_a.innerHTML= '<img style="cursor:pointer" src="'+a1a+'" onclick="document.getElementById(\'full_img\').src=\''+a1b+'\'; document.getElementById(\'full_img_a\').href=\''+a1c+'\'" id="img_pre1">';
    var a1a = addr+'/_photos/s_'+position[write_position+2];
    var a1b = addr+'/_photos/m_'+position[write_position+2];
    var a1c = addr+'/_photos/'+position[write_position+2];
    img3_a.innerHTML= '<img style="cursor:pointer" src="'+a1a+'" onclick="document.getElementById(\'full_img\').src=\''+a1b+'\'; document.getElementById(\'full_img_a\').href=\''+a1c+'\'" id="img_pre2">';
  
  	link1.innerHTML = "<img src=\""+addr+"/obrazy/sipka-vlevo.jpg\" onclick=\"change_images( '"+addr+"', 'left', " + write_position +" );\" alt='Left' />";
  	link2.innerHTML = "<img src=\""+addr+"/obrazy/sipka-vpravo.jpg\" onclick=\"change_images( '"+addr+"', 'right', " + write_position +" );\" alt='Right' />";
}