diff --git a/td/telegram/MessageContent.cpp b/td/telegram/MessageContent.cpp
index a7f89ebf..26f078fd 100644
--- a/td/telegram/MessageContent.cpp
+++ b/td/telegram/MessageContent.cpp
@@ -2958,12 +2958,17 @@ void merge_message_contents(Td *td, const MessageContent *old_content, MessageCo
           }
         }
 
+        LOG(DEBUG) << "Merge photos " << old_photo->photos << " and " << new_photo->photos
+                   << " with new photos size = " << new_photos_size << ", need_merge = " << need_merge
+                   << ", need_update = " << need_update;
         if (need_merge && new_photos_size != 0) {
           FileId old_file_id = get_message_content_upload_file_id(old_content);
           FileView old_file_view = td->file_manager_->get_file_view(old_file_id);
           FileId new_file_id = new_photo->photos[0].file_id;
           FileView new_file_view = td->file_manager_->get_file_view(new_file_id);
           CHECK(new_file_view.has_remote_location());
+
+          LOG(DEBUG) << "Trying to merge old file " << old_file_id << " and new file " << new_file_id;
           if (new_file_view.remote_location().is_web()) {
             LOG(ERROR) << "Have remote web photo location";
           } else if (!old_file_view.has_remote_location() ||
diff --git a/td/telegram/files/FileManager.cpp b/td/telegram/files/FileManager.cpp
index 67c2d1e7..335e6608 100644
--- a/td/telegram/files/FileManager.cpp
+++ b/td/telegram/files/FileManager.cpp
@@ -1327,6 +1327,7 @@ Result<FileId> FileManager::merge(FileId x_file_id, FileId y_file_id, bool no_sy
   }
 
   if (!y_file_id.is_valid()) {
+    LOG(DEBUG) << "Old file is invalid";
     return x_node->main_file_id_;
   }
   FileNodePtr y_node = get_file_node(y_file_id);
@@ -1338,6 +1339,7 @@ Result<FileId> FileManager::merge(FileId x_file_id, FileId y_file_id, bool no_sy
     x_node->set_upload_pause(FileId());
   }
   if (x_node.get() == y_node.get()) {
+    LOG(DEBUG) << "Files are already merged";
     return x_node->main_file_id_;
   }
   if (y_file_id == y_node->upload_pause_) {
@@ -2422,6 +2424,7 @@ void FileManager::delete_file_reference(FileId file_id, string file_reference) {
   if (remote != nullptr) {
     VLOG(file_references) << "Do delete file reference of remote file " << file_id;
     if (remote->delete_file_reference(file_reference)) {
+      VLOG(file_references) << "Successfully deleted file reference of remote file " << file_id;
       node->upload_was_update_file_reference_ = false;
       node->download_was_update_file_reference_ = false;
       node->on_pmc_changed();