Show all PNGs + size and posts used in

* Really slow, might not make it on big DB's.

functions.php

@@ -378,3 +378,137 @@ function ( $urls, $post_id ) {
 	10,
 	2
 );
+
+/**
+ * Given an attachment ID, searches for any post with that attachment used
+ * as a featured image, or if it is present in the content of the post.
+ * (Note above known issues).
+ */
+function get_image_posts( $id ){
+	global $wpdb;
+
+	$att  = get_post_custom( $id );
+	$file = $att['_wp_attached_file'][0];
+	//Do not take full path as different image sizes could
+	// have different month, year folders due to theme and image size changes
+	$file = sprintf(
+		"%s.%s",
+		pathinfo( $file, PATHINFO_FILENAME ),
+		pathinfo( $file, PATHINFO_EXTENSION )
+	);
+
+	$sql = "SELECT {$wpdb->posts}.ID
+        FROM {$wpdb->posts}
+        INNER JOIN {$wpdb->postmeta}
+        ON ({$wpdb->posts}.ID = {$wpdb->postmeta}.post_id)
+        WHERE {$wpdb->posts}.post_type IN ('post', 'page', 'campaign', 'action')
+        AND (({$wpdb->posts}.post_status = 'publish'))
+        AND ( ({$wpdb->postmeta}.meta_key = '_thumbnail_id'
+            AND CAST({$wpdb->postmeta}.meta_value AS CHAR) = '%d')
+            OR ( {$wpdb->posts}.post_content LIKE %s )
+        )
+        GROUP BY {$wpdb->posts}.ID";
+
+	$prepared_sql = $wpdb->prepare( $sql, $id, "%src=\"%" . $wpdb->esc_like( $file ) . "\"%" );
+
+	return $wpdb->get_col( $prepared_sql );
+}
+
+/**
+ * Returns the size of a file without downloading it, or -1 if the file
+ * size could not be determined.
+ *
+ * @param $url - The location of the remote file to download. Cannot
+ * be null or empty.
+ *
+ * @return The size of the file referenced by $url, or -1 if the size
+ * could not be determined.
+ */
+function curl_get_file_size( $url ) {
+	// Assume failure.
+	$result = - 1;
+
+	$curl = curl_init( $url );
+
+	// Issue a HEAD request and follow any redirects.
+	curl_setopt( $curl, CURLOPT_NOBODY, true );
+	curl_setopt( $curl, CURLOPT_HEADER, true );
+	curl_setopt( $curl, CURLOPT_RETURNTRANSFER, true );
+	curl_setopt( $curl, CURLOPT_FOLLOWLOCATION, true );
+
+	$data = curl_exec( $curl );
+	curl_close( $curl );
+	if ( $data ) {
+		$content_length = "unknown";
+		$status         = "unknown";
+
+		if ( preg_match( "/^HTTP\/1\.[01] (\d\d\d)/", $data, $matches ) ) {
+			$status = (int) $matches[1];
+		}
+
+		if ( preg_match( "/Content-Length: (\d+)/", $data, $matches ) ) {
+			$content_length = (int) $matches[1];
+		}
+
+		// http://en.wikipedia.org/wiki/List_of_HTTP_status_codes
+		if ( $status == 200 || ( $status > 300 && $status <= 308 ) ) {
+			$result = $content_length;
+		}
+	}
+
+	return $result;
+}
+
+function formatBytes( $size, $precision = 2 ) {
+	$base     = log( $size, 1024 );
+	$suffixes = array( '', 'K', 'M', 'G', 'T' );
+
+	return round( 1024 ** ( $base - floor( $base ) ), $precision ) . ' ' . $suffixes[ floor( $base ) ];
+}
+
+add_menu_page(
+	__( 'PNG checkup', 'planet4-master-theme-backend' ),
+	__( 'PNG checkup', 'planet4-master-theme-backend' ),
+	'edit_posts',
+	'png-checkup',
+	function () {
+		$args = [
+			'post_type'      => 'attachment',
+			'posts_per_page' => - 1,
+			'post_status'    => 'any',
+			'post_mime_type' => 'image/png',
+		];
+
+		$results = new WP_Query( $args );
+
+		echo "<h1>PNG Report</h1>";
+		echo '<table>';
+		foreach ( $results->posts as $image ) {
+			echo '<tr>';
+			$id         = $image->ID;
+			$src        = wp_get_attachment_image_src( $id, 'full' )[0];
+			$title      = get_the_title( $id );
+			$size_check = curl_get_file_size( $src );
+			$size       = $size_check <= 0 ? '' : formatBytes( $size_check );
+			echo "<td><a href=\"$src\">#$id ($title)</a></td>";
+			echo "<td>size: $size</td>";
+			$image_posts = get_image_posts( $id );
+
+			echo '<td>';
+			echo '<ul>';
+			foreach ( $image_posts as $id ) {
+				$src       = get_permalink( $id );
+				$edit_link = get_edit_post_link( $id );
+				$title     = get_the_title( $id );
+				echo "<li><a href=\"$src\">#$id ($title)</a> ";
+				echo "<a href=\"$edit_link\">Edit</a></li>";
+			}
+			echo '</ul>';
+			echo '</td>';
+			echo '</tr>';
+		}
+		echo '</table>';
+	},
+	'dashicons-format-image',
+	11
+);