diff --git a/course/renderer.php b/course/renderer.php
index 4894ff901e1..2db11d1d89d 100644
--- a/course/renderer.php
+++ b/course/renderer.php
@@ -1210,7 +1210,7 @@ class core_course_renderer extends plugin_renderer_base {
                 $file->get_filearea() . $file->get_filepath() . $file->get_filename(), !$isimage);
             if ($isimage) {
                 $contentimages .= html_writer::tag('div',
-                    html_writer::empty_tag('img', ['src' => $url]),
+                    html_writer::empty_tag('img', ['src' => $url, 'alt' => '']),
                     ['class' => 'courseimage']);
             } else {
                 $image = $this->output->pix_icon(file_file_icon($file, 24), $file->get_filename(), 'moodle');