function show_main_img(to_do,alt_value)
{
	if(to_do==0)
	{
		if(current_image==1)
		{
			alert("This is first image");

		}
		else
		{
			current_image--;
			document.getElementById("main_img").innerHTML='<img src="/php/image.php/pic'+current_image+'.jpg?width=350&amp;height=350&amp;image='+arr_digital[2][current_image]+'" alt="'+alt_value+'"  >';
		}
	}
	if(to_do==1)
	{
		if(current_image>=digital_rows)
		{
			alert("This is last image");

		}
		else
		{
			current_image++;
			document.getElementById("main_img").innerHTML='<img src="/php/image.php/pic'+current_image+'.jpg?width=350&amp;height=350&amp;image='+arr_digital[2][current_image]+'"  alt="'+alt_value+'"   >';
		}
	}
	
}