if (document.images) {
books = new Image(200,45); books.src = "../images/nav/books.gif";
books_on = new Image(200,45); books_on.src = "../images/nav/books_on.gif";
autographs = new Image(200,45); autographs.src = "../images/nav/autographs.gif";
autographs_on = new Image(200,45); autographs_on.src = "../images/nav/autographs_on.gif";
maps = new Image(200,45); maps.src = "../images/nav/maps.gif";
maps_on = new Image(200,45); maps_on.src = "../images/nav/maps_on.gif";
prints = new Image(200,45); prints.src = "../images/nav/prints.gif";
prints_on = new Image(200,45); prints_on.src = "../images/nav/prints_on.gif";
photographs = new Image(175,40); photographs.src = "../images/photographs.gif";
photographs_on = new Image(175,40); photographs_on.src = "../images/photographs_on.gif";
broadsides = new Image(200,45); broadsides.src = "../images/nav/broadsides.gif";
broadsides_on = new Image(200,45); broadsides_on.src = "../images/nav/broadsides_on.gif";
fineart = new Image(175,40); fineart.src = "../images/fineart.gif";
fineart_on = new Image(175,40); fineart_on.src = "../images/fineart_on.gif";
collections = new Image(175,40); collections.src = "../images/collections.gif";
collections_on = new Image(175,40); collections_on.src = "../images/collections.gif";
}
/* Function that swaps images. */
function di20(id, newSrc) {
    var theImage = FWFindImage(document, id, 0);
    if (theImage) {
        theImage.src = newSrc;
    }
}

/* Functions that track and set toggle group button states. */

function FWFindImage(doc, name, j) {
    var theImage = false;
    if (doc.images) {
        theImage = doc.images[name];
    }
    if (theImage) {
        return theImage;
    }
    if (doc.layers) {
        for (j = 0; j < doc.layers.length; j++) {
            theImage = FWFindImage(doc.layers[j].document, name, 0);
            if (theImage) {
                return (theImage);
            }
        }
    }
    return (false);
}