Question

I have created a custom post type called banners and want to enable the thumbnails in that post type. Hence I have put the following code just after the starting tag on my functions file but the banners post type still are not showing featured image option in the admin panel.

if ( function_exists( 'add_theme_support' ) ) { 
  add_theme_support( 'post-thumbnails', array( 'banner' ) );
}

If I replace the banner with post or page the featured image option does show up in the respective menu options.

Answer 1

You need to make sure that your custom post type allows the use of the featured image. Here is an example of a custom post type with thumbnails allowed:

<?php
function your_custom_post_types() {
    // Portfolio
    $labels_portfolio = array(
        'add_new' => __('Add New', 'portfolio'),
        'add_new_item' => __('Add Portfolio Item'),
        'edit_item' => __('Edit Portfolio Post'),
        'menu_name' => __('Portfolio'),
        'name' => __('Portfolio', 'post type general name'),
        'new_item' => __('New Portfolio Item'),
        'parent_item_colon' => '',
        'singular_name' => __('Portfolio Post', 'post type singular name'),
        'view_item' => __('View Portfolio Item'),
    );
    $args_portfolio = array(
        'capability_type' => 'post',
        'has_archive' => true, 
        'hierarchical' => false,
        'labels' => $labels_portfolio,
        'menu_position' => 4,
        'public' => true,
        'publicly_queryable' => true,
        'query_var' => true,
        'rewrite' => array( 'slug' => 'portfolio', 'with_front' => true ),
        'show_in_menu' => true, 
        'show_ui' => true, 
        'supports' => array( 'comments', 'editor', 'excerpt', 'thumbnail', 'title' ),
    );
    register_post_type( 'portfolio', $args_portfolio );
}
?>

The line that allows the thumbnail is this one:

'supports' => array( 'comments', 'editor', 'excerpt', 'thumbnail', 'title'