In order to add an image for the Page Title Background in the Blog category listing pages, please follow the steps below:
The Blog category listing pages are automatically generated from Wordpress and they don't have local Vamtam options like the standard ones. They use the default theme's options.
Example for Blog category listing pages:
Please go to the global VamTam option panel in Dashboard > Vamtam > General Settings > Tribe Events > Listing > edit or remove the Title Background image
Click the "Save changes" button