On my blog page i have selected the following options
Header layout: Transparent header dark
page title layout: Centre parrallax large
Page title background image type: Featured image
I have set a featured image, yet the blog page shows up as plain white.
I am using the same settings for all my other pages and the respective background shows up.
The website is under maintenance so you will need to login to view the page.
The reason you can’t see header background image in blog page is because you have set this page as Posts page in Settings > Reading.
So you will need to go to Appearance > Customier > Blog to change the header settings for this blog page.
Otherwise, if you want to use page setting for blog page, please refer to the document here for creating blog page with Visual Composer: http://www.themelogi.com/docs/roneous/#!/create_blog_page (you can only use page settings if the page is not set as Posts page in Settings > Reading)