#####----- Show zoomed picture -----#####
# $zoom is number between -4 and 3;  Negative for zoom-out and positive for zoom-in as worked out in the conditional statement.
# $img is the original image.
# $zimg is the zoomed image.
$zimg = $MW->Photo();
($zoom > 0) ? $zimg->copy($img, -zoom      => $zoom)
            : $zimg->copy($img, -subsample => ($zoom * -1));
$CW->createImage(0,0, -anchor => 'nw', -image => $zimg, -tags => 'dwg');