Images in sidebar

“Main Course” is a Page – not a Post. In Twenty Eleven, Pages do not have a sidebar. The only way around this is to start developing your own custom child theme.

‘main course’ seems to be set as ‘posts page’, and therefore shows a sidebar.

for all other pages, use the ‘sidebar template’;

under:

dashboard – pages – edit page – page attributes – template

single posts also will have no sidebr; if you need a sidebar, try to use a plugin such as https://www.ads-software.com/extend/plugins/twenty-eleven-theme-extensions/

it will be general a good idea to create and use a child theme.

@alchymyth Brilliant, thanks for that advice!