Show image search only if there is a suitable host

boards/config/default_settings.ini

@@ -45,4 +45,4 b' ArchiveThreads = true'
 MaxItems = 20
 
 [External]
-ImageSearchHost=http://127.0.0.1/
+ImageSearchHost=

boards/models/attachment/viewers.py

@@ -186,23 +186,25 b' class ImageViewer(AbstractViewer):'
     def get_context_menu(self):
         items = super().get_context_menu()
 
-        image_url = settings.get('External', 'ImageSearchHost') + self.file.url
+        image_host = settings.get('External', 'ImageSearchHost')
+        if image_host:
+            image_url = image_host + self.file.url
 
-        items.append({
-            'name': 'google',
-            'label': 'Google',
-            'url': 'https://www.google.com/searchbyimage?image_url={}'.format(image_url),
-        })
-        items.append({
-            'name': 'iqdb',
-            'label': 'iqdb',
-            'url': 'http://iqdb.org/?url={}'.format(image_url)
-        })
-        items.append({
-            'name': 'tineye',
-            'label': 'TinEye',
-            'url': 'http://tineye.com/search?url={}'.format(image_url)
-        })
+            items.append({
+                'name': 'google',
+                'label': 'Google',
+                'url': 'https://www.google.com/searchbyimage?image_url={}'.format(image_url),
+            })
+            items.append({
+                'name': 'iqdb',
+                'label': 'iqdb',
+                'url': 'http://iqdb.org/?url={}'.format(image_url)
+            })
+            items.append({
+                'name': 'tineye',
+                'label': 'TinEye',
+                'url': 'http://tineye.com/search?url={}'.format(image_url)
+            })
 
         return items