I want to display custom static content, essentially an image and a small description, at the top of each category page (different for each category and sub category), displayed above a list of titles of the category posts with excerpts. 

Is there an automated solution/plugin available for this? I need an automated way to insert text/image too because I want to pass this to my content writer and he will take care of the new categories. A rich text editor where I can insert image and text, which will be assigned to a category and can be shown on top of the category page.