diff --git a/BUGS.md b/BUGS.md
index c1afd25..2ea1eeb 100644
--- a/BUGS.md
+++ b/BUGS.md
@@ -11,7 +11,6 @@
 
 # TODO
 
-- servir imagens/ficheiros.
 - session management. close after inactive time.
 - each topic only loads a sample of K questions (max) in random order.
 - radio e checkboxes, aceitar numeros como seleccao das opcoes.
@@ -30,6 +29,7 @@
 
 # FIXED
 
+- servir imagens/ficheiros.
 - radio: suporte para multiplas opcoes correctas e erradas, escolhendo-se uma selecção aleatoria destas (so com 1 certa).
 - checkbox: cada opção pode ser uma dupla (certo, errado) sendo escolhida uma aleatória.
 - async/threadpool no bcrypt do initdb.
diff --git a/demo/solar_system/questions.yaml b/demo/solar_system/questions.yaml
index 6e891b7..63bd8bd 100644
--- a/demo/solar_system/questions.yaml
+++ b/demo/solar_system/questions.yaml
@@ -1,20 +1,23 @@
 ---
 
-# # ---------------------------------------------------------------------------
-# -
-#     ref: solar-system
-#     type: radio
-#     title: Sistema solar
-#     text: Qual é o maior planeta do Sistema Solar?
-#     options:
-#         - Mercúrio
-#         - Marte
-#         - Júpiter
-#         - Têm todos o mesmo tamanho
-#     # opcional
-#     correct: 2
-#     shuffle: False
-#     discount: True
+# ---------------------------------------------------------------------------
+-
+    ref: solar-system
+    type: radio
+    title: Sistema solar
+    text: |
+        ![planetas](planetsa.png " Planetas do Sistema Solar")
+
+        Qual é o maior planeta do Sistema Solar?
+    options:
+        - Mercúrio
+        - Marte
+        - Júpiter
+        - Têm todos o mesmo tamanho
+    # opcional
+    correct: 2
+    shuffle: False
+    discount: True
 
 # # ---------------------------------------------------------------------------
 # -
diff --git a/serve.py b/serve.py
index 92e721d..a735fb0 100755
--- a/serve.py
+++ b/serve.py
@@ -30,8 +30,8 @@ class WebApplication(tornado.web.Application):
             (r'/change_password', ChangePasswordHandler),
             (r'/question',      QuestionHandler),       # each question
             (r'/topic/(.+)',    TopicHandler),          # page for doing a topic
-            # (r'/file/(.+)',   FileHandler),   # FIXME
-            (r'/.*',            RootHandler),           # show list of topics
+            (r'/file/(.+)',     FileHandler),   # FIXME
+            (r'/',              RootHandler),           # show list of topics
         ]
         settings = {
             'template_path': path.join(path.dirname(__file__), 'templates'),
@@ -143,20 +143,36 @@ class TopicHandler(BaseHandler):
                 self.redirect('/')
 
 # ----------------------------------------------------------------------------
-# FIXME
+# Based on https://bhch.github.io/posts/2017/12/serving-large-files-with-tornado-safely-without-blocking/
 class FileHandler(BaseHandler):
     @tornado.web.authenticated
-    def get(self, filename):
+    async def get(self, filename):
         uid = self.current_user
         public_dir = self.learn.get_current_public_dir(uid)
         filepath = path.expanduser(path.join(public_dir, filename))
+        chunk_size = 1024 * 1024 # serve 1MiB multiple times
         try:
             f = open(filepath, 'rb')
         except FileNotFoundError:
-            raise tornado.web.HTTPError(404)
+            logging.error(f'File not found: {filepath}')
+        except PermissionError:
+            logging.error(f'No permission: {filepath}')
         else:
-            self.write(f.read())
-            f.close()
+            with f:
+                while True:
+                    chunk = f.read(chunk_size)
+                    if not chunk: break
+                    try:
+                        self.write(chunk)   # write the cunk to response
+                        await self.flush()  # flush the current chunk to socket
+                    except iostream.StreamClosedError:
+                        # client closed the connection
+                        break
+                    finally:
+                        del chunk
+                        await gen.sleep(0.000000001) # 1 nanosecond (hack)
+                        # in tornnado 5.0 use `await asyncio.sleep(0)` instead
+
 
 # ----------------------------------------------------------------------------
 # respond to AJAX to get a JSON question
diff --git a/tools.py b/tools.py
index f45a110..4fbb5d5 100644
--- a/tools.py
+++ b/tools.py
@@ -99,19 +99,10 @@ class HighlightRenderer(mistune.Renderer):
     def table(self, header, body):
         return '<table class="table table-sm"><thead class="thead-light">' + header + '</thead><tbody>' + body + "</tbody></table>"
 
-    # def image(self, src, title, text):
-    #     if src.startswith('javascript:'):
-    #         src = ''
-    #     text = mistune.escape(text, quote=True)
-    #     if title:
-    #         title = mistune.escape(title, quote=True)
-    #         html = '<img class="img-responsive center-block" src="%s" alt="%s" title="%s"' % (src, text, title)
-    #     else:
-    #         html = '<img class="img-responsive center-block" src="%s" alt="%s"' % (src, text)
-    #     if self.options.get('use_xhtml'):
-    #         return '%s />' % html
-    #     return '%s>' % html
-
+    def image(self, src, title, alt):
+        alt = mistune.escape(alt, quote=True)
+        title = mistune.escape(title or '', quote=True)
+        return f'<img src="/file/{src}" class="img-fluid mx-auto d-block" alt="{alt}" title="{title}">'
 
     # Pass math through unaltered - mathjax does the rendering in the browser
     def block_math(self, text):
--
libgit2 0.21.2