diff --git a/de.systopia.civiproxy/CRM/Civiproxy/Mailer.php b/de.systopia.civiproxy/CRM/Civiproxy/Mailer.php
index 1b9c9e1..a020090 100644
--- a/de.systopia.civiproxy/CRM/Civiproxy/Mailer.php
+++ b/de.systopia.civiproxy/CRM/Civiproxy/Mailer.php
@@ -59,6 +59,7 @@ class CRM_Civiproxy_Mailer {
     $value = preg_replace("#{$system_base}sites/all/modules/civicrm/extern/open.php#i", $proxy_base.'/open.php',        $value);
     $value = preg_replace("#{$system_base}sites/default/files/civicrm/persist/#i",      $proxy_base.'/file.php?id=',    $value);
     $value = preg_replace("#{$system_base}civicrm/mosaico/img\?src=#i",                 $proxy_base.'/mosaico.php?id=', $value);
+    $value = preg_replace("#{$system_base}civicrm/mosaico/img/\?src=#i",                 $proxy_base.'/mosaico.php?id=', $value);
 
     // Mailing related functions
     $value = preg_replace("#{$system_base}civicrm/mailing/view#i",                      $proxy_base.'/mailing/mail.php', $value);