Header image disappears when page set to 'display posts'

Can we see the site using your latest posts on the front page?

I will activate it now – but will have to uno it as someone is editing site. here goes…

Did yuo see it?
I have saved a screenshot here:
https://www.diigo.com/item/image/397ka/nua6

No. These are volunteer forums and volunteers have other things to do – like eat, sleep and earn a living. You can’t make a change for just 4 minutes and expect someone to see it. You have to make the change and then leave it until someone responds.

https://www.ads-software.com/support/topic/twentyeleven-featured-image-does-work-for-a-page-that-is-designated-to-show-post?replies=5

https://pastebin.com/CkfkPxAU

(might be for an older version of Twenty Eleven; check how the corresponding section looks in the latest version, and edit accordingly)

Thank you alchymyth, I will look and see if I can understand it.
Incidentally, I realise I have set the same thing up in another site and it works perfectly!!
https://www.hotel-devon.org see the ‘Managers column’ – the image stays there and the posts allow commenting. But I can not get this to happen in the other site.
Theme: Twenty Eleven
WP: 3.5.1

just looked at the linked site, and for instance in a category archive, it is not showing a header image (although the code is output to the browser) because the image link is somehow broken through a missing /:

this is the html of the header image as output to the browser:

<img src="https://davidandlindaking.orgwp-content/themes/twentyeleven/images/headers/hanoi.jpg" width="1000" height="288" alt="" />

there should be a / after the .org from the site url

right now, I have no idea why custom (featured) images for the header work fine, while the build-in ones are missing the slash /

possibly check the entries under settings – general – WordPress Address / Site Address (?)

Thank you Alchymtyh – I’ll check…