core: gen thumb, small, readme for every image

src/picture.py

@@ -33,6 +33,8 @@ class Picture():
         if (config.CREATE_GENERAL_ALBUM):
             self._albums_name.append("general")
         self._is_reperoried: bool = is_repertoried
+        self.gen_small()
+        self.gen_thumb()
 
     def get_page(self):
         return self._page