Again, thank you both for your time, and assistance.

I made the change suggested, and it worked ... well, I didn't have doubts.

As for the path, I tried both and
<?php echo zen_image(DIR_WS_LANGUAGES . 'images/' . $_SESSION['language'] . '/' . 'image1.gif', 'Your alt & title text for image here')?>
doesn't display the images, whereas Glenn's suggestion does.