detect images

src/rss.py

@@ -34,6 +34,10 @@ def line2words(lines, limit):
         output.append("...")
     return output
 
+def _is_image_token(token: str, extensions):
+    parts = token.rsplit('.', 1)
+    return len(parts) == 2 and parts[1] in extensions
+
 # this is similar to the markup function in microblog
 def enrich_msg(lines, is_atom=True):
     if not is_atom: