diff --git a/app/activitypub/util.py b/app/activitypub/util.py
index 461d8077..63c419e3 100644
--- a/app/activitypub/util.py
+++ b/app/activitypub/util.py
@@ -125,24 +125,24 @@ def post_to_activity(post: Post, community: Community):
         ],
         "object": {
             "id": create_id,
-            "actor": f"https://{current_app.config['SERVER_NAME']}/u/{post.author.user_name}",
+            "actor": post.author.ap_public_url,
             "to": [
                 "https://www.w3.org/ns/activitystreams#Public"
             ],
             "object": {
                 "type": "Page",
-                "id": f"https://{current_app.config['SERVER_NAME']}/post/{post.id}",
-                "attributedTo": f"https://{current_app.config['SERVER_NAME']}/u/{post.author.user_name}",
+                "id": post.ap_id,
+                "attributedTo": post.author.ap_public_url,
                 "to": [
                     f"https://{current_app.config['SERVER_NAME']}/c/{community.name}",
                     "https://www.w3.org/ns/activitystreams#Public"
                 ],
                 "name": post.title,
                 "cc": [],
-                "content": post.body_html,
+                "content": post.body_html if post.body_html else '',
                 "mediaType": "text/html",
                 "source": {
-                    "content": post.body,
+                    "content": post.body if post.body else '',
                     "mediaType": "text/markdown"
                 },
                 "attachment": [],
@@ -704,6 +704,9 @@ def make_image_sizes_async(file_id, thumbnail_width, medium_width, directory):
                         content_type_parts = content_type.split('/')
                         if content_type_parts:
                             file_ext = '.' + content_type_parts[-1]
+                    else:
+                        if '?' in file_ext:
+                            file_ext = file_ext.split('?')[0]
 
                     new_filename = gibberish(15)
 
diff --git a/app/community/util.py b/app/community/util.py
index 6fc2b438..b07e2c16 100644
--- a/app/community/util.py
+++ b/app/community/util.py
@@ -211,7 +211,7 @@ def save_post(form, post: Post):
                     filename = opengraph.get('og:image') or opengraph.get('og:image:url')
                     filename_for_extension = filename.split('?')[0] if '?' in filename else filename
                     unused, file_extension = os.path.splitext(filename_for_extension)
-                    if file_extension.lower() in allowed_extensions:
+                    if file_extension.lower() in allowed_extensions and not filename.startswith('/'):
                         file = url_to_thumbnail_file(filename)
                         if file:
                             file.alt_text = opengraph.get('og:title')