adds getSiteImage function

src/View/Helper/ArchiveSiteMetaViewHelper.php

@@ -95,6 +95,23 @@ class ArchiveSiteMetaViewHelper extends AbstractHelper
         return null;
     }
 
+    public function getSiteImage($site)
+    {
+      foreach ($site->pages() as $page) {
+        foreach ($page->blocks() as $block) {
+            if ($block->layout() === 'archiveSiteMeta') {
+              $attachments = $block->attachments();
+              //if (!$attachments) {
+              //    return null;
+              //}
+              $media = $attachments[0]->item()->media()[0];
+              return $media->primaryMedia()->thumbnailUrl('large');
+            }
+        }
+      }
+      return null;
+    }
+
     /**
      * @return \Omeka\Api\Representation\SiteRepresentation
      */