Hi Dave,
Changing the height property should make the container higher. Did you change the height property back in the CSS? When I look in the code the height is still 450px. The best way to edit the css is in the custom CSS section of your WP theme (if it has one). And then setting it with an !important property like so:
#zoomifyContainer {
height: 900px!important;
}
This will override the plugin stylesheet for the height.
Another reason could be that the browsercache has saved the stylesheet and still loading the old one after you edit zoomify-styles.css. You can ‘break’ the saved cache in your browser by adding a version number to the plugin’s wp_enqueue_style() function.
I will add the version parameter to the latest version of the plugin, but you can change it manually by copying this line of code and replacing the existing one in gh-zoomify.php.
wp_enqueue_style('gh-zoomify', GH_ZOOMIFY_BASE . 'assets/css/zoomify-styles.css', '', '1.0');
The last parameter (1.0) is the version number. If you change it to a higher number anytime you edit the stylesheet, your browser will load the latest version of the stylesheet.
Thanks for your question!