diff --git a/admin/settings/appearance.php b/admin/settings/appearance.php
index 707f07670ae..cd69ecc3b79 100644
--- a/admin/settings/appearance.php
+++ b/admin/settings/appearance.php
@@ -253,10 +253,13 @@ preferences,moodle|/user/preferences.php|t/preferences',
             new lang_string('courselistshortnames_desc', 'admin'), 0));
     $temp->add(new admin_setting_configtext('coursesperpage', new lang_string('coursesperpage', 'admin'), new lang_string('configcoursesperpage', 'admin'), 20, PARAM_INT));
     $temp->add(new admin_setting_configtext('courseswithsummarieslimit', new lang_string('courseswithsummarieslimit', 'admin'), new lang_string('configcourseswithsummarieslimit', 'admin'), 10, PARAM_INT));
+
     $temp->add(new admin_setting_configtext('courseoverviewfileslimit', new lang_string('courseoverviewfileslimit'),
             new lang_string('configcourseoverviewfileslimit', 'admin'), 1, PARAM_INT));
-    $temp->add(new admin_setting_configtext('courseoverviewfilesext', new lang_string('courseoverviewfilesext'),
-            new lang_string('configcourseoverviewfilesext', 'admin'), '.jpg,.gif,.png'));
+    $temp->add(new admin_setting_filetypes('courseoverviewfilesext', new lang_string('courseoverviewfilesext'),
+        new lang_string('configcourseoverviewfilesext', 'admin'), 'web_image'
+    ));
+
     $temp->add(new admin_setting_configtext('coursegraceperiodbefore', new lang_string('coursegraceperiodbefore', 'admin'),
         new lang_string('configcoursegraceperiodbefore', 'admin'), 0, PARAM_INT));
     $temp->add(new admin_setting_configtext('coursegraceperiodafter', new lang_string('coursegraceperiodafter', 'admin'),
diff --git a/course/lib.php b/course/lib.php
index 63f191c85ae..0752586c015 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -2276,31 +2276,18 @@ function course_overviewfiles_options($course) {
     if (empty($CFG->courseoverviewfileslimit)) {
         return null;
     }
-    $accepted_types = preg_split('/\s*,\s*/', trim($CFG->courseoverviewfilesext), -1, PREG_SPLIT_NO_EMPTY);
-    if (in_array('*', $accepted_types) || empty($accepted_types)) {
-        $accepted_types = '*';
-    } else {
-        // Since config for $CFG->courseoverviewfilesext is a text box, human factor must be considered.
-        // Make sure extensions are prefixed with dot unless they are valid typegroups
-        foreach ($accepted_types as $i => $type) {
-            if (substr($type, 0, 1) !== '.') {
-                require_once($CFG->libdir. '/filelib.php');
-                if (!count(file_get_typegroup('extension', $type))) {
-                    // It does not start with dot and is not a valid typegroup, this is most likely extension.
-                    $accepted_types[$i] = '.'. $type;
-                    $corrected = true;
-                }
-            }
-        }
-        if (!empty($corrected)) {
-            set_config('courseoverviewfilesext', join(',', $accepted_types));
-        }
+
+    // Create accepted file types based on config value, falling back to default all.
+    $acceptedtypes = (new \core_form\filetypes_util)->normalize_file_types($CFG->courseoverviewfilesext);
+    if (in_array('*', $acceptedtypes) || empty($acceptedtypes)) {
+        $acceptedtypes = '*';
     }
+
     $options = array(
         'maxfiles' => $CFG->courseoverviewfileslimit,
         'maxbytes' => $CFG->maxbytes,
         'subdirs' => 0,
-        'accepted_types' => $accepted_types
+        'accepted_types' => $acceptedtypes
     );
     if (!empty($course->id)) {
         $options['context'] = context_course::instance($course->id);
diff --git a/course/tests/category_test.php b/course/tests/category_test.php
index 5d463dec0d1..467f89d028d 100644
--- a/course/tests/category_test.php
+++ b/course/tests/category_test.php
@@ -906,7 +906,7 @@ class core_course_category_testcase extends advanced_testcase {
 
         // Reset default settings.
         $CFG->courseoverviewfileslimit = 1;
-        $CFG->courseoverviewfilesext = '.jpg,.gif,.png';
+        $CFG->courseoverviewfilesext = 'web_image';
 
         $courses = $cat1->get_courses();
         $this->assertTrue($courses[$c1->id]->has_course_overviewfiles());