diff --git a/components/ILIAS/Test/classes/class.ilTestHTMLGenerator.php b/components/ILIAS/Test/classes/class.ilTestHTMLGenerator.php
index a14d9e89b2db..6fd3402ab413 100755
--- a/components/ILIAS/Test/classes/class.ilTestHTMLGenerator.php
+++ b/components/ILIAS/Test/classes/class.ilTestHTMLGenerator.php
@@ -78,21 +78,46 @@ private function makeHtmlDocument($content_html, $style_html): string
 
         $dom->encoding = 'UTF-8';
 
+        $content_to_replace = $this->generateImageDataSrces($dom);
+
+        $cleaned_html = $dom->saveHTML();
+
+        if (!$cleaned_html) {
+            return $html;
+        }
+
+        if ($content_to_replace === null) {
+            return $cleaned_html;
+        }
+
+        return str_replace(array_keys($content_to_replace), array_values($content_to_replace), $cleaned_html);
+    }
+
+    private function generateImageDataSrces(DOMDocument $dom): ?array
+    {
         $content_to_replace = null;
+        $sources = [];
+        $image_file_names = [];
         foreach ($dom->getElementsByTagName('img') as $elm) {
             /** @var $elm DOMElement $uid */
             $src = $elm->getAttribute('src');
+            $original_content = $dom->saveHTML($elm);
 
-            $src_uri = new ILIAS\Data\URI($src);
-            $path_to_file = $_SERVER['DOCUMENT_ROOT'] . $src_uri->getPath();
+            if (array_key_exists($src, $sources)) {
+                $replacement_content = preg_replace('/src=[^\s]*/', "src='{$sources[$src]}'", $original_content);
+                $content_to_replace[$original_content] = $replacement_content;
+                continue;
+            }
 
             try {
-                $image_content = base64_encode(file_get_contents($path_to_file));
+                $image_raw_content = file_get_contents($src);
+                $image_file_names[$src] = ilFileUtils::ilTempnam();
+                file_put_contents($image_file_names[$src], $image_raw_content);
+                $image_content = base64_encode($image_raw_content);
                 $file_info = finfo_open(FILEINFO_MIME_TYPE);
-                $mime_type = finfo_file($file_info, $path_to_file);
+                $mime_type = finfo_file($file_info, $image_file_names[$src]);
                 $image_data = "data:{$mime_type};base64,{$image_content}";
-
-                $original_content = $dom->saveHTML($elm);
+                $sources[$src] = $image_data;
                 $replacement_content = preg_replace('/src=[^\s]*/', "src='{$image_data}'", $original_content);
                 $content_to_replace[$original_content] = $replacement_content;
             } catch (Exception $e) {
@@ -100,17 +125,11 @@ private function makeHtmlDocument($content_html, $style_html): string
             }
         }
 
-        $cleaned_html = $dom->saveHTML();
-
-        if (!$cleaned_html) {
-            return $html;
-        }
-
-        if ($content_to_replace === null) {
-            return $cleaned_html;
+        foreach ($image_file_names as $image_file_name) {
+            unlink($image_file_name);
         }
 
-        return str_replace(array_keys($content_to_replace), array_values($content_to_replace), $cleaned_html);
+        return $content_to_replace;
     }
 
     public function generateHTML(string $content, string $filename)