How can I move the default Featured Image Meta Box position from the right column to the big left column, by using a php script or existing plugin. It should be moved right under the title for all Post Types including custom post types, not only for a specific Post Type?
If you look up the action do_meta_boxes you will see that it will pass you the post_type as a parameter to your callback function (here you have chosen not to accept any of them). You can use that post_type to then make the changes to your meta boxes.
/* Move Featured Image Below Title */
function move_featured_image_box($post_type) {
remove_meta_box( 'postimagediv', $post_type, 'side' );
add_meta_box(
'postimagediv', __('Featured Image'),
'post_thumbnail_meta_box', $post_type, 'normal', 'high'
);
}
add_action(‘do_meta_boxes’, ‘move_featured_image_box’);
I have not tested this, but based on the documentation for do_meta_boxes you see as part of the call to the action the first parameter is the post_type. This value is then passed to any actions that are subscribed. So we add in the parameter to your callback and with that we can act on the post type. In theory this should work.