The header images in the archive, category, search results and author pages are all added via PHP as Divi Library Layouts.

Navigate to Divi > Divi Library in the WordPress menu.

In the library there are 4 layouts under the category Archive Page Headers: Category Page Header, Search Results Header, Archive Page Header and Author Page Header. 

Open each of the these layouts and change the text and background images in the Call to Action modules to your own. You will also want to change the text in the module named Ophelia to your own.