If you're looking for a feature that will allow you to define some additonal custom contents for your category pages - this guide is exactly for you. Based on this tutorial you can create additional descriptions (images, custom code etc.) separated from default "description" on category pages. Each category can have own unique content - this means that you can put some customization for any category you want.
Custom contents on category pages
now your block will appear only on selected category page. Of course you can create such block on each category page, or on more category pages. You can create unlimited blocks in this hook, and you can also create new hooks and put them to category.tpl file. In that way you will have possibility to create unlimited number of places, where you will be able to use custom contents. Videoguide attached below.