Jetpack Tiled Gallery block image links

add_filter( 'render_block', function( $block_content, $block ) {

	// Jetpack Tiled Gallery Block Only
	if( $block['blockName'] != 'jetpack/tiled-gallery' ) {
		return $block_content;
	}

	// Loop Image IDs
	foreach( $block['attrs']['ids'] as $post_id ) {

		// Get Caption And Ensure It's a URL
		$caption = wp_get_attachment_caption( $post_id );
		if( ! $caption || filter_var( $caption, FILTER_VALIDATE_URL ) === false ) {
			continue;
		}

		// Replace Image Tag With Anchor
		// Note We're Altering The Figure Tags To Iterate
		$block_content = preg_replace(
			'/' . preg_quote( '<figure class="tiled-gallery__item">' ) . '/',
			'<a href="' . $caption . '"><figure  class="tiled-gallery__item">',
			$block_content,
			1
		);
		$block_content = preg_replace(
			'/<\/figure>/',
			'</figure ></a>',
			$block_content,
			1
		);

	}

	// Return
	return $block_content;

}, 10, 2 );