Add image caching to jetpack_og_get_image() (#6297)

* Add image caching to jetpack_og_get_image()

This adds a transient to store the value of the $image_id to "speed up"  the function to fix #6017

* Added missing semicolons at EOL on a couple lines

* Adding some whitespace per coding standards

functions.opengraph.php

@@ -313,7 +313,13 @@ function jetpack_og_get_image( $width = 200, $height = 200, $max_images = 4 ) {
 
 			$img_width  = '';
 			$img_height = '';
-			$image_id = attachment_url_to_postid( $image_url );
+			$cached_image_id = get_transient( 'jp_' . $image_url );
+			if ( false !== $cached_image_id ) {
+				$image_id = $cached_image_id;
+			} else {
+				$image_id = attachment_url_to_postid( $image_url );
+				set_transient( 'jp_' . $image_url, $image_id );
+			}
 			$image_size = wp_get_attachment_image_src( $image_id, $width >= 512
 				? 'full'
 				: array( $width, $width ) );
@@ -351,7 +357,15 @@ function jetpack_og_get_image( $width = 200, $height = 200, $max_images = 4 ) {
 
 		$img_width  = '';
 		$img_height = '';
-		$image_id = get_option( 'site_icon' );
+		$cached_image_id = get_transient( 'jp_' . $image_url );
+
+		if ( false !== $cached_image_id ) {
+			$image_id = $cached_image_id;
+		} else {
+			$image_id = attachment_url_to_postid( $image_url );
+			set_transient( 'jp_' . $image_url, $image_id );
+		}
+
 		$image_size = wp_get_attachment_image_src( $image_id, $max_side >= 512
 			? 'full'
 			: array( $max_side, $max_side ) );