By default, The Events Calendar enables featured images on all event custom post types. However, some themes remove this functionality by declaring thumbnail support for only specific custom post types. You can use the snippet below to add back support for our event custom post type.
In the functions.php file in your currently active theme, add the line of code below to add back thumbnail support for Event custom post types.
We work hard to make our plugins compatible with as many themes as possible, but inevitably some theme’s need a bit of custom code (like this snippet) to work smoothly with our plugins. If your theme removes support for featured images on our events, you can always get in touch with your theme’s developer and recommend that they update to be more compatible with our custom post types.
add_theme_support( 'post-thumbnails', [
'post',
'page',
'tribe_events',
] );