From 5dd61d9f56c89ea8a2be8c02ab648d3d9b5b6091 Mon Sep 17 00:00:00 2001
From: Alexander Ebert <ebert@woltlab.com>
Date: Sun, 16 Jan 2022 15:18:03 +0100
Subject: [PATCH] Enable lazy loading of media thumbnails

---
 .../install/files/lib/data/media/ViewableMedia.class.php | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/wcfsetup/install/files/lib/data/media/ViewableMedia.class.php b/wcfsetup/install/files/lib/data/media/ViewableMedia.class.php
index 40bb353fd1..3b12914abc 100644
--- a/wcfsetup/install/files/lib/data/media/ViewableMedia.class.php
+++ b/wcfsetup/install/files/lib/data/media/ViewableMedia.class.php
@@ -209,7 +209,14 @@ class ViewableMedia extends DatabaseObjectDecorator
             throw new \InvalidArgumentException("Unknown thumbnail size '" . $size . "'");
         }
 
-        return '<img src="' . StringUtil::encodeHTML($this->getThumbnailLink($size)) . '" alt="' . StringUtil::encodeHTML($this->altText) . '" ' . ($this->title ? 'title="' . StringUtil::encodeHTML($this->title) . '" ' : '') . 'style="width: ' . $this->getThumbnailWidth($size) . 'px; height: ' . $this->getThumbnailHeight($size) . 'px;">';
+        return \sprintf(
+            '<img src="%s" alt="%s" width="%d" height="%d" loading="lazy" %s>',
+            StringUtil::encodeHTML($this->getThumbnailLink($size)),
+            StringUtil::encodeHTML($this->altText),
+            $this->getThumbnailWidth($size),
+            $this->getThumbnailHeight($size),
+            ($this->title ? 'title="' . StringUtil::encodeHTML($this->title) . '" ' : '')
+        );
     }
 
     /**
-- 
2.20.1