Module random image PHP Error after 3.8.8
From Joomla! Documentation
Errors reported[edit]
Fatal error: Using $this when not in object context in .../modules/mod_random_image/tmpl/default.php on line 16
Versions affected[edit]
General Information
This pertains only to Joomla! version(s): 3.8.8
What is the cause[edit]
Modules don't have $this context, so can't call $this->escape(). Escape output using htmlspecialchars() instead.
How to fix[edit]
Apply this patch https://github.com/joomla/joomla-cms/pull/20533/files