function showPicture(num, imgLoading)
  {
		
		// same image
		if( (n > 1) && (num == n) )
		  return;
		
		
		// reset memo
		var memo_row = document.getElementById("memo_row");
		var memo = document.getElementById("memo");
		
		if( !((num == 0) && (currPage == 1 )) )
		{
		if( memo_row != null )
		 	memo_row.style.visibility = "hidden";
		if( memo != null )
		 	memo.innerHTML = ""; 	
		}
		
		
		// lame workaround
		if( (num == 1) && (n == 1) ) // show first image on page load 
			n = 0;
	
	 // move between pages
	 //  next page
	 if( (num > all) && (currPage < numOfPages) )
	 {
	 		document.location = "page" + ( currPage + 1 ) + ".html";
			return;
	 }
	 // previous page
	 else if( (num == 0) && (currPage > 1 ) )
	 {
	 		document.location = "page" + ( currPage - 1 ) + ".html";
			return;
	 }

	 
	 // move between images
	 
	 if ( (num <= all) && (num > 0) )
   {
   	 var img = new Image();
   	 var picture = document.getElementById("picture");
   	 
		 
   	 picture.src = imgLoading;
   	 picture.src = "images/" + fotos[num] + ".jpg";
 
   	 
   	 // memo
   	 if( (memo != null) && (memos[num] != "") )
   	 {
   	 	memo.innerHTML = memos[num];
   	 	if( memo_row != null )
   	 		memo_row.style.visibility = "visible";
   	 }
  
		 b = document.getElementById("b"+num); 
		 b.className = "num_button_active";
     b.blur();

		 // deactivate previous button
     if( n > 0 )
      document.getElementById("b"+n).className = "num_button";

		 // back & forward buttons
		 b_forward = document.getElementById("forward_button");
		 b_back = document.getElementById("back_button");
		 
		 if( (num == all) && (currPage == numOfPages) )
		 {
		 	b_forward.style.visibility = "hidden";
		 }	
		 else
		 {
		 	b_forward.style.visibility = "visible";			 		
			b_forward.blur();
		 }
		 
		 if( (num == 1) && (currPage == 1) )
		 {
		 	b_back.style.visibility = "hidden";
		 }	
		 else
		 {
		 	b_back.style.visibility = "visible";			 		
			b_back.blur();
		 }

     n = num;
     self.scrollTo(0,0);
   }
  }