If anyone wants an easy way to remove 1.3 prior to installing 1.4 and have shell access, make the needed changes and run this from the root of your zen folder:
Code:
rm -v ./includes/functions/extra_functions/zen_image_lightbox_IH2_url.php
rm -v ./includes/modules/YOUR_TEMPLATE/additional_images.php
rm -v ./includes/modules/pages/product_info/jscript_lightbox.php
rm -v ./includes/templates/YOUR_TEMPLATE/css/stylesheet_lightbox.css
rm -v ./includes/templates/YOUR_TEMPLATE/templates/tpl_modules_main_product_image.php
rm -v ./includes/templates/template_default/images/lightbox/
rm -v ./includes/templates/template_default/images/lightbox/Thumbs.db
rm -v ./includes/templates/template_default/images/lightbox/blank.gif
rm -v ./includes/templates/template_default/images/lightbox/close.gif
rm -v ./includes/templates/template_default/images/lightbox/closelabel.gif
rm -v ./includes/templates/template_default/images/lightbox/loading.gif
rm -v ./includes/templates/template_default/images/lightbox/nextlabel.gif
rm -v ./includes/templates/template_default/images/lightbox/prevlabel.gif
rm -v ./includes/templates/template_default/jscript/lightbox.js
rm -v ./includes/templates/template_default/jscript/lightbox_effects.js
rm -v ./includes/templates/template_default/jscript/lightbox_prototype.js
rm -v ./includes/templates/template_default/jscript/lightbox_scriptaculous.js