post featured images disappeared from theme

hi there

i have tried changing a theme from tesseract to twenty eleven , in order to get the sidebar to work inside the posts

after returning to tesseract back i saw that my posts featured images are no longer visible as well as the main sidebar which both worked before

i can see the images in the featured image box when i edit the post , and when i enter the post , but on the main posts page i can’t see them .

i deactivating all plugins and adding the “add_theme_support( ‘post-thumbnails’ );” into functions.php but no luck so far

the site is https://www.producerdish.com

any help will be more than appreciated
thanks
dish