Snippet: Remove the WPBakery Post Grid Blue Fallback Featured Image

function myprefix_remove_vc_grid_fallback_img( $output ) {
	if ( ! get_post_thumbnail_id() ) {
		return;
	}
	return $output;
}
add_filter( 'vc_gitem_template_attribute_post_image_url', 'myprefix_remove_vc_grid_fallback_img', 99 );
add_filter( 'vc_gitem_template_attribute_post_image_background_image_css_value', 'myprefix_remove_vc_grid_fallback_img', 99 );