src/Post.php
public function featured_image_url( $size = 'thumbnail', $default = '' ) {
		$featured_image = \get_the_post_thumbnail_url( $this->id(), $size );
		return ( false !== $featured_image ) ? $featured_image : $default;
	}
public function featured_image_url( $size = 'thumbnail', $default = '' ) {
		$featured_image = \get_the_post_thumbnail_url( $this->id(), $size );
		return ( false !== $featured_image ) ? $featured_image : $default;
	}
public function featured_image_url ( $ size = 'thumbnail' , $ default = '' ) { $ featured_image = \ get_the_post_thumbnail_url ( $ this -> id ( ) , $ size ) ; return ( false !== $ featured_image ) ? $ featured_image : $ default ; }
Returns Featured Image URL.

@param string $size
@param string $default

@return false|string
Returns Featured Image URL .