Pintrest button generating link to blank image.

The plugin is being used on this site:
http://andreafisherdesign.com/wp/gallery/early-1900s-print-fragonard/

The link being generated for the pintrest button is:
https://www.pinterest.com/pin/create/button/?url=http%3A%2F%2Fandreafisherdesign.com%2Fwp%2Fgallery%2Fearly-1900s-print-fragonard%2F&media=https%3A%2F%2Fs0.wp.com%2Fi%2Fblank.jpg&description=Antique%20print%20after%20Fragonard

So its linking to this image (blank):
https://s0.wp.com/i/blank.jpg

But its supposed to link to this image:
http://andreafisherdesign.com/wp/wp-content/uploads/2014/08/TheSwingEngravingWithoutFrame21-615×593.jpg

And as such, generate the following link:
https://www.pinterest.com/pin/create/button/?url=http%3A%2F%2Fandreafisherdesign.com%2Fwp%2Fgallery%2Fearly-1900s-print-fragonard%2F&media=http%3A%2F%2Fandreafisherdesign.com%2Fwp%2Fwp-content%2Fuploads%2F2014%2F08%2FTheSwingEngravingWithoutFrame21-615×593.jpg&xm=h&xv=cr1.39.1&xuid=s1ptTnBca7CJ&description=Antique+print+after+Fragonard+

I found the code where this is happening but I can’t figure out how to fix it.

public function get_name() {
		return __( 'Pinterest', 'jetpack' );
	}

	public function get_image( $post ) {
		if ( class_exists( 'Jetpack_PostImages' ) ) {
			$image = Jetpack_PostImages::get_image( $post->ID, array( 'fallback_to_avatars' => true ) );
			if ( ! empty( $image ) ) {
				return $image['src'];
			}
		}

		/**
		 * Filters the default image used by the Pinterest Pin It share button.
		 *
		 * @module sharedaddy
		 *
		 * @since 3.6.0
		 *
		 * @param string $url Default image URL.
		 */
		return apply_filters( 'jetpack_sharing_pinterest_default_image', 'https://s0.wp.com/i/blank.jpg' );
	}

	public function get_external_url( $post ) {
		$url = 'https://www.pinterest.com/pin/create/button/?url=' . rawurlencode( $this->get_share_url( $post->ID ) ) . '&media=' . rawurlencode( $this->get_image( $post ) ) . '&description=' . rawurlencode( $post->post_title );

		/**
		 * Filters the Pinterest share URL used in sharing button output.
		 *
		 * @module sharedaddy
		 *
		 * @since 3.6.0
		 *
		 * @param string $url Pinterest share URL.
		 */
		return apply_filters( 'jetpack_sharing_pinterest_share_url', $url );
	}

I’m guessing that it thinks there is no image to return? Any ideas on how to fix this?

https://wordpress.org/plugins/jetpack-sharing/