Quick fix for the threads list API

boards/models/post/__init__.py

@@ -200,7 +200,12 b' class Post(models.Model, Viewable):'
         return self.get_view(need_op_data=True, *args, **kwargs)
 
     def get_first_image(self) -> Attachment:
-        return self.attachments.filter(mimetype__in=FILE_TYPES_IMAGE).earliest('id')
+        image = None
+        try:
+            image = self.attachments.filter(mimetype__in=FILE_TYPES_IMAGE).earliest('id')
+        except Attachment.DoesNotExist:
+            pass
+        return image
 
     def set_global_id(self, key_pair=None):
         """

boards/models/post/export.py

@@ -37,10 +37,10 b' class JsonExporter(Exporter):'
             'title': post.title,
             'text': post.get_raw_text(),
             }
-        if post.attachments.exists():
-            post_image = post.get_first_image()
+        post_image = post.get_first_image()
+        if post_image:
             post_json['image'] = post_image.file.url
-            post_json['image_preview'] = post_image.get_preview_url()
+            post_json['image_preview'] = post_image.get_thumb_url()
         if include_last_update:
             post_json['bump_time'] = utils.datetime_to_epoch(
                 post.get_thread().bump_time)