diff --git a/plugins/af_zz_imgproxy/init.php b/plugins/af_zz_imgproxy/init.php
index 5fab3b7b..8419b8a8 100644
--- a/plugins/af_zz_imgproxy/init.php
+++ b/plugins/af_zz_imgproxy/init.php
@@ -124,7 +124,7 @@ class Af_Zz_ImgProxy extends Plugin {
 				$parts = parse_url($url);
 
 				foreach (explode(" " , $this->ssl_known_whitelist) as $host) {
-					if (strpos($parts['host'], $host) !== FALSE) {
+					if (substr(strtolower($parts['host']), -strlen($host)) === strtolower($host)) {
 						$parts['scheme'] = 'https';
 
 						return build_url($parts);