@Anton.D
In readme file is stated:
------- How to change category images on main page? ------
"Use FontAwesome icons instead of small image icons for categories on homepage" in theme settings is enabled
- go to http://fortawesome.github.io/Font-Awesome/icons/ and choose icons you like (important is name of icon that is in format: fa-NAME)
- go to oc-admin > Appearance > Theme Settings
- in right column (Font-Awesome icon) click "Add / Remove icon" link
-- to add new icon to category place it's name to input (i.e.: fa-basket or fa-home or fa-bank ...)
-- to remove icon, leave input blan
- note that for default categories in osclass there are default values for icons saved in main.php, you do not need to modify this file
"Use FontAwesome icons instead of small image icons for categories on homepage" in theme settings is disabled
- go to oc-admin > Appearance > Theme settings
- at bottom of page there is Category Image Management
-- Small Image is image used in homepage in category tabs, png format is acceptable only
-- Large Image is image used as banner for category (on homepage in category section - left side), jpg format is acceptable only
I am not sure what is not clear.