This tutorial provides the solution which enables you to change the background image on posts based on which category the post is assigned to.
Based on the following question from a member of the genesis community :
How can I change the background on a post based on the category of the post? I.E. – I have a series of post topics in Category 1, another series of post topics in Category 2. All posts in Category 1 are to have Cat1.jpg for the background, all topics in Category 2 are to have Cat2.jpg for the background.
Shows how the same background image once added to the edit category screen can be displayed on all posts in the same category as well as the category page itself. Also shows how a default image can be set to display on single posts in the same category when one hasn’t been added yet to the category edit screen. And also shows how the image added to the customizer is used as the background on all other pages.
Here’s the code snippets which provide 2 different solutions :