Post thumbnails not working in my new install of WP 3.1 with Twenty Ten theme

Question

I am working in a new project, and I just realized that in the page/post edit pages, I don´t have the option to set a featured image/ post thumbnail.

I have checked and Twenty Ten has thumbnails support by default ( add_theme_support( 'post-thumbnails' is in functions.php). I also tried setting the thumbnails size with set_post_thumbnail_size, but no luck.

Any ideas?

P.D: I installed this in a new server, is it possible that it has something to do with that? Are there any specific requirements to use post thumbnails?

Answer 1

The featured image meta box is enabled under following conditions:

if ( current_theme_supports( 'post-thumbnails', $post_type ) && post_type_supports( $post_type, 'thumbnail' )
    && ( ! is_multisite() || ( ( $mu_media_buttons = get_site_option( 'mu_media_buttons', array() ) ) && ! empty( $mu_media_buttons['image'] ) ) ) )
        add_meta_box('postimagediv', __('Featured Image'), 'post_thumbnail_meta_box', $post_type, 'side', 'low');

So check that:

• nothing messes up theme's declaration of thumbnails support;
• you are not using CPT with thumbnails support undeclared;
• whatever that multisite-related stuff means, if you are using multisite (I do and I don't remember having to do anything specific for featured images).