What does it do:
This modification to the code allows the category and sub-category images to be used in the categories box.
If a category or sub-category has no image then the textual name is shown.
The code can be ammended to give both a category or sub-category image and textual name.
I have included some files that can be used as replacements, these files if used require to be renamed categories.php and would replace the file in catalog/includes/boxes/categories.php
categories_main_images.php -- This gives main category images only.
categories_main_images_text.php -- This gives main category images with text.
categories_main_sub_images.php -- This gives main category and sub-category images.
categories_main_sub_images_text.php -- This gives main category images with text and sub-category images with text.