sub show_next_image {
    my( $id, $filename ) = get_next_pic();
    my $raw_image = $Image_Window->Photo( '-format' => 'jpeg',
                                          -file => $filename );

    my ($img_w, $img_h) = ($raw_image->width, $raw_image->height);  
    my $max_width = $Main->screenwidth()-20;
    my $max_height = $Main->screenheight()-75;
    my $xfactor = $img_w / $max_width;
    my $yfactor = $img_h / $max_height;

    my $intfactor = $xfactor > $yfactor ? int($xfactor) : int($yfactor);
    $intfactor += 1;

    my $image = $Image_Window->Photo();
    $image->copy( $raw_image,
                  -subsample => $intfactor);

    my $reduced_flag = ( $raw_image->width == $image->width ) ? 
        'full-size' : "reduced by $intfactor";

    $Image_Window->delete( '0.1', 'end' );
    $Image_Window->insert( '0.1', "$reduced_flag\n" );
    my $image_widget = $Image_Window->imageCreate( 'end', -image => $image );

    $raw_image->destroy();
    $image->destroy();
}