var loaded = false;
var galleryIndex = [];

function checkImages()
{
	if( loaded )
		return( true );

	if( typeof images == 'undefined' )
		return( false );

	return( true );

}

function loadImages()
{
	if( ! checkImages() )
		return( false );

	if( document.images )
	{
		var i = null;
		for( i = 0; i < images.length; i++ )
		{
			galleryIndex[i]     = new Image();
			galleryIndex[i].src = images[i];
			//.src = ;
		}
	}

	loaded = true;
}

function changeImage( id, index, trigger )
{
    alt_text = "Nordic Tugs";
    if(trigger != null) {
        alt_src = document.getElementById( trigger );
        alt_text = alt_src.getAttribute("alt");
    }
    
	if( ! checkImages() )
		return( false );

	if( ! loaded )
		loadImages();

	var el = document.getElementById( id );
	if( ! el || ! el.src )
		return( false );

	el.src = galleryIndex[ index ].src;
	el.setAttribute("alt", alt_text);
	el.setAttribute("title", alt_text);
}