diff --git a/blocks/online_users/block_online_users.php b/blocks/online_users/block_online_users.php
index dbdf802097b..e44468cae6a 100644
--- a/blocks/online_users/block_online_users.php
+++ b/blocks/online_users/block_online_users.php
@@ -126,7 +126,8 @@ class block_online_users extends block_base {
                 } else { // Not a guest user.
                     $this->content->text .= '<div class="user">';
                     $this->content->text .= '<a href="'.$CFG->wwwroot.'/user/view.php?id='.$user->id.'&amp;course='.$this->page->course->id.'" title="'.$timeago.'">';
-                    $this->content->text .= $OUTPUT->user_picture($user, array('size'=>16, 'alttext'=>false, 'link'=>false)) .$user->fullname.'</a></div>';
+                    $avataroptions = ['size' => 16, 'visibletoscreenreaders' => false, 'link' => false];
+                    $this->content->text .= $OUTPUT->user_picture($user, $avataroptions) . $user->fullname . '</a></div>';
 
                     if ($USER->id == $user->id) {
                         if ($CFG->block_online_users_onlinestatushiding) {
diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index b2a76c37d7d..172834e4bbc 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -2511,8 +2511,6 @@ class core_renderer extends renderer_base {
      * @return string
      */
     protected function render_user_picture(user_picture $userpicture) {
-        global $CFG, $DB;
-
         $user = $userpicture->user;
         $canviewfullnames = has_capability('moodle/site:viewfullnames', $this->page->context);
 
@@ -2545,11 +2543,10 @@ class core_renderer extends renderer_base {
         $attributes = array('src' => $src, 'class' => $class, 'width' => $size, 'height' => $size);
         if (!$userpicture->visibletoscreenreaders) {
             $alt = '';
-            $attributes['aria-hidden'] = 'true';
         }
+        $attributes['alt'] = $alt;
 
         if (!empty($alt)) {
-            $attributes['alt'] = $alt;
             $attributes['title'] = $alt;
         }