tweaks to link for image subsearch 4, a=chris

diff --git a/src/views/helpers/ImagesHelper.php b/src/views/helpers/ImagesHelper.php
index 80e6aab67..39beefca6 100644
--- a/src/views/helpers/ImagesHelper.php
+++ b/src/views/helpers/ImagesHelper.php
@@ -58,7 +58,7 @@ class ImagesHelper extends Helper implements CrawlConstants
             if ($image_subsearch) {
                 $query .= '&s=images';
             } else {
-                if (!stristr($query, media:image)) {
+                if (!stristr($query, "media:image")) {
                     $query .= '%20media:image';
                 }
             }