For anyone who is having problems getting the Product Information Image Width & Product Information Image Height to change the product image. It seems there is a step missing from the install instructions and the product image is still getting it's dimensions from the Small Image setting.
In product_info.php around line 147, find:
$product_info['products_image'], $product_info['products_name'], SMALL_IMAGE_WIDTH, SMALL_IMAGE_HEIGHT,
and change it to:
$product_info['products_image'], $product_info['products_name'], PRODUCT_INFO_IMAGE_WIDTH, PRODUCT_INFO_IMAGE_HEIGHT,