Hello, I need to give a different style to the images, differentiating them by category. Thus, a category will have all images with a frame background (a background image) and one category will have another frame (another background image). The images loaded now in the default style "image" of k2.css. I do not know how to separate this style by assigning different categories, or failing that, where could insert on what php file for each category like that ... Does anyone could help me?

You cannot have different CSS files per category. You can make a template override for each category and apply different classes to the elements you like depending on category. After that you can style each class however you like.

Thanks! really was easy to resolve. I had to create differents templates based in actual default template and assign each them in backend. Thanks again.

You are welcome.