diff --git a/modules/purchase_trade/process_documentation.py b/modules/purchase_trade/process_documentation.py
index 52a3180..804d4a7 100644
--- a/modules/purchase_trade/process_documentation.py
+++ b/modules/purchase_trade/process_documentation.py
@@ -15,6 +15,8 @@ from trytond.transaction import Transaction
 
 DOCUMENTATION_ROOT = Path(__file__).with_name('process_documentation')
 MARKDOWN_LINK = re.compile(r'(!?)\[([^\]]*)\]\(([^)]+)\)')
+HTML_IMAGE_SOURCE = re.compile(
+    r'(<img\b[^>]*\bsrc=)(["\'])([^"\']+)(\2)', re.IGNORECASE)
 
 
 class ProcessDocumentation(ModelSingleton, ModelSQL, ModelView):
@@ -50,13 +52,30 @@ def _html_file_content(filename):
     common_path = os.path.commonpath([str(root), str(path)])
     if path != root and common_path == str(root):
         if path.exists() and path.is_file() and path.suffix.lower() == '.html':
+            document = path.read_text(encoding='utf-8')
+            document = _inline_html_assets(document, _relative_name(path))
             return IFRAME_TEMPLATE % {
-                'document': html.escape(path.read_text(encoding='utf-8'),
-                    quote=True),
+                'document': html.escape(document, quote=True),
                 }
     return _html_error('Documentation page not found: %s' % filename)
 
 
+def _inline_html_assets(document, current_file):
+    def replace(match):
+        prefix, quote, source, suffix = match.groups()
+        resolved = _resolve_link(current_file, source)
+        if resolved.startswith(('http://', 'https://', 'data:', 'mailto:')):
+            return match.group(0)
+
+        data_uri = _asset_data_uri(resolved)
+        if not data_uri:
+            return match.group(0)
+        return '%s%s%s%s' % (prefix, quote, html.escape(data_uri, quote=True),
+            suffix)
+
+    return HTML_IMAGE_SOURCE.sub(replace, document)
+
+
 def _html_error(message):
     document = HTML_TEMPLATE % {
         'content': '<p>%s</p>' % html.escape(message),
diff --git a/modules/purchase_trade/process_documentation/ITSA/Operations_Workflow.html b/modules/purchase_trade/process_documentation/ITSA/Operations_Workflow.html
index e042027..bfa2256 100644
--- a/modules/purchase_trade/process_documentation/ITSA/Operations_Workflow.html
+++ b/modules/purchase_trade/process_documentation/ITSA/Operations_Workflow.html
@@ -382,7 +382,7 @@
           <li>Contract lines: product, quantity, unit, tolerance, price formula, Mtm.</li>
         </ul>
         <div class="screenshot-placeholder">
-          <img src="../assets/purchase_contract_header.png" alt="Purchase contract header">
+          <img src="assets/purchase_contract_header.png" alt="Purchase contract header">
         </div>
       </div>
     </td>