diff --git a/common/framework/filters/htmlfilter.php b/common/framework/filters/htmlfilter.php
index bfedc28f2..9afe6879a 100644
--- a/common/framework/filters/htmlfilter.php
+++ b/common/framework/filters/htmlfilter.php
@@ -263,6 +263,7 @@ class HTMLFilter
 		// Support additional properties.
 		$def->addAttribute('i', 'aria-hidden', 'Text');
 		$def->addAttribute('img', 'srcset', 'Text');
+		$def->addAttribute('img', 'data-file-srl', 'Number');
 		$def->addAttribute('iframe', 'allowfullscreen', 'Bool');
 	}