diff --git a/main/inc/ajax/exercise.ajax.php b/main/inc/ajax/exercise.ajax.php
index 5637788ae2..c9c30e4cfb 100755
--- a/main/inc/ajax/exercise.ajax.php
+++ b/main/inc/ajax/exercise.ajax.php
@@ -140,7 +140,10 @@ switch ($action) {
                             GROUP by question_id
                         ) as count_table";
                 $result_count = Database::query($sql);
-                $count_questions = Database::fetch_array($result_count,'ASSOC');
+                $count_questions = Database::fetch_array(
+                    $result_count,
+                    'ASSOC'
+                );
                 $count_questions = $count_questions['count_question_id'];
 
                 $row['count_questions'] = $count_questions;
diff --git a/main/inc/lib/api.lib.php b/main/inc/lib/api.lib.php
index 9885999efc..abeda17b37 100644
--- a/main/inc/lib/api.lib.php
+++ b/main/inc/lib/api.lib.php
@@ -1459,8 +1459,10 @@ function api_get_user_info(
     $apcVar = null;
     $user = false;
     $cacheAvailable = api_get_configuration_value('apc');
+
     if (empty($user_id)) {
         $userFromSession = Session::read('_user');
+
         if (isset($userFromSession)) {
             if (!empty($cacheAvailable)) {
                 $apcVar = api_get_configuration_value('apc_prefix') . 'userinfo_' . $userFromSession['user_id'];
diff --git a/main/inc/lib/banner.lib.php b/main/inc/lib/banner.lib.php
index dca8c0b673..a83b73ff61 100755
--- a/main/inc/lib/banner.lib.php
+++ b/main/inc/lib/banner.lib.php
@@ -552,20 +552,19 @@ function return_breadcrumb($interbreadcrumb, $language_file, $nameTools)
 
         switch (api_get_setting('breadcrumbs_course_homepage')) {
             case 'get_lang':
-                
-                $navigation_item['title'] = Display::return_icon('home.png', get_lang('CourseHomepageLink'), null, ICON_SIZE_TINY);
+                $navigation_item['title'] = Display::return_icon('home.png', get_lang('CourseHomepageLink'), [], ICON_SIZE_TINY);
                 break;
             case 'course_code':
-                $navigation_item['title'] =  Display::return_icon('home.png', $_course['official_code'], null, ICON_SIZE_TINY).' '.$_course['official_code'];
+                $navigation_item['title'] =  Display::return_icon('home.png', $_course['official_code'], [], ICON_SIZE_TINY).' '.$_course['official_code'];
                 break;
             case 'session_name_and_course_title':
-                $navigation_item['title'] = Display::return_icon('home.png', $_course['name'].$my_session_name, null, ICON_SIZE_TINY).' '.$course_title.$my_session_name;
+                $navigation_item['title'] = Display::return_icon('home.png', $_course['name'].$my_session_name, [], ICON_SIZE_TINY).' '.$course_title.$my_session_name;
                 break;
             default:
                 if (api_get_session_id() != -1 ) {
-                    $navigation_item['title'] = Display::return_icon('home.png', $_course['name'].$my_session_name, null, ICON_SIZE_TINY).' '.$course_title.$my_session_name;
+                    $navigation_item['title'] = Display::return_icon('home.png', $_course['name'].$my_session_name, [], ICON_SIZE_TINY).' '.$course_title.$my_session_name;
                 } else {
-                    $navigation_item['title'] = Display::return_icon('home.png', $_course['name'], null, ICON_SIZE_TINY).' '.$course_title;
+                    $navigation_item['title'] = Display::return_icon('home.png', $_course['name'], [], ICON_SIZE_TINY).' '.$course_title;
                 }
                 break;
         }
diff --git a/main/inc/lib/course_home.lib.php b/main/inc/lib/course_home.lib.php
index 5e65ba3a54..79d1323c84 100755
--- a/main/inc/lib/course_home.lib.php
+++ b/main/inc/lib/course_home.lib.php
@@ -1290,7 +1290,7 @@ class CourseHome
                 $html .= Display::return_icon(
                     substr($navigation_item['image'], 0, -3).'png',
                     $navigation_item['name'],
-                    null,
+                    [],
                     ICON_SIZE_MEDIUM
                 );
                 $html .= '</a> ';
diff --git a/main/inc/lib/display.lib.php b/main/inc/lib/display.lib.php
index d52fd708fc..e32cd5ca2e 100755
--- a/main/inc/lib/display.lib.php
+++ b/main/inc/lib/display.lib.php
@@ -805,7 +805,6 @@ class Display
 
         if ($return_only_path) {
             return $icon;
-
         }
 
         $img = self::img($icon, $alt_text, $additional_attributes);
@@ -827,7 +826,7 @@ class Display
      * @param boolean $filterPath Optional. Whether filter the image path. Default is true
      * @author Julio Montoya 2010
      */
-    public static function img($image_path, $alt_text = '', $additional_attributes = array(), $filterPath = true)
+    public static function img($image_path, $alt_text = '', $additional_attributes = null, $filterPath = true)
     {
         if (empty($image_path)) {
             // For some reason, the call to img() happened without a proper
@@ -848,6 +847,10 @@ class Display
             $alt_text = basename($image_path);
         }
 
+        if (empty($additional_attributes)) {
+            $additional_attributes = [];
+        }
+
         $additional_attributes['src'] = $image_path;
 
         if (empty($additional_attributes['alt'])) {
diff --git a/main/inc/lib/template.lib.php b/main/inc/lib/template.lib.php
index 70ea5f6e6b..3c89049dd2 100755
--- a/main/inc/lib/template.lib.php
+++ b/main/inc/lib/template.lib.php
@@ -801,8 +801,14 @@ class Template
             }
         }
 
-        $this->assign('online_button', Display::return_icon('statusonline.png', null, null, ICON_SIZE_ATOM));
-        $this->assign('offline_button',Display::return_icon('statusoffline.png', null, null, ICON_SIZE_ATOM));
+        $this->assign(
+        'online_button',
+            Display::return_icon('statusonline.png', null, [], ICON_SIZE_ATOM)
+        );
+        $this->assign(
+            'offline_button',
+            Display::return_icon('statusoffline.png', null, [], ICON_SIZE_ATOM)
+        );
 
         // Get language iso-code for this page - ignore errors
         $this->assign('document_language', api_get_language_isocode());
@@ -894,7 +900,7 @@ class Template
 
         //@todo move this in the template
         $rightFloatMenu = '';
-        $iconBug = Display::return_icon('bug.png', get_lang('ReportABug'), null, ICON_SIZE_LARGE);
+        $iconBug = Display::return_icon('bug.png', get_lang('ReportABug'), [], ICON_SIZE_LARGE);
         if (api_get_setting('show_link_bug_notification') == 'true' && $this->user_is_logged_in) {
             $rightFloatMenu = '<div class="report">
 		<a href="https://github.com/chamilo/chamilo-lms/wiki/How-to-report-issues" target="_blank">
@@ -905,7 +911,7 @@ class Template
 
         if (api_get_setting('show_link_ticket_notification') == 'true' && $this->user_is_logged_in) {
             // by default is project_id = 1
-            $iconTicket = Display::return_icon('bug.png', get_lang('Ticket'), null, ICON_SIZE_LARGE);
+            $iconTicket = Display::return_icon('bug.png', get_lang('Ticket'), [], ICON_SIZE_LARGE);
             $courseInfo = api_get_course_info();
             $courseParams = '';
             if (!empty($courseInfo)) {