diff --git a/td/telegram/DocumentsManager.cpp b/td/telegram/DocumentsManager.cpp
index fe627416b..af952d5dc 100644
--- a/td/telegram/DocumentsManager.cpp
+++ b/td/telegram/DocumentsManager.cpp
@@ -319,10 +319,10 @@ Document DocumentsManager::on_get_document(RemoteDocument remote_document, Dialo
     }
 
     if (document_type != Document::Type::VoiceNote) {
-      for (auto &thumb : document->thumbs_) {
+      for (auto &thumbnail_ptr : document->thumbs_) {
         auto photo_size = get_photo_size(td_->file_manager_.get(), PhotoSizeSource::thumbnail(FileType::Thumbnail, 0),
                                          id, access_hash, file_reference, DcId::create(dc_id), owner_dialog_id,
-                                         std::move(thumb), thumbnail_format);
+                                         std::move(thumbnail_ptr), thumbnail_format);
         if (photo_size.get_offset() == 0) {
           if (!thumbnail.file_id.is_valid()) {
             thumbnail = std::move(photo_size.get<0>());
@@ -332,22 +332,22 @@ Document DocumentsManager::on_get_document(RemoteDocument remote_document, Dialo
         }
       }
     }
-    for (auto &thumb_ptr : document->video_thumbs_) {
-      if (thumb_ptr->get_id() != telegram_api::videoSize::ID) {
+    for (auto &thumbnail_ptr : document->video_thumbs_) {
+      if (thumbnail_ptr->get_id() != telegram_api::videoSize::ID) {
         continue;
       }
-      auto thumb = move_tl_object_as<telegram_api::videoSize>(thumb_ptr);
-      if (thumb->type_ == "v") {
+      auto video_size = move_tl_object_as<telegram_api::videoSize>(thumbnail_ptr);
+      if (video_size->type_ == "v") {
         if (!animated_thumbnail.file_id.is_valid()) {
           animated_thumbnail =
               get_animation_size(td_, PhotoSizeSource::thumbnail(FileType::Thumbnail, 0), id, access_hash,
-                                 file_reference, DcId::create(dc_id), owner_dialog_id, std::move(thumb));
+                                 file_reference, DcId::create(dc_id), owner_dialog_id, std::move(video_size));
         }
-      } else if (thumb->type_ == "f") {
+      } else if (video_size->type_ == "f") {
         if (!premium_animation_file_id.is_valid()) {
           premium_animation_file_id =
               register_photo_size(td_->file_manager_.get(), PhotoSizeSource::thumbnail(FileType::Thumbnail, 'f'), id,
-                                  access_hash, file_reference, owner_dialog_id, thumb->size_, DcId::create(dc_id),
+                                  access_hash, file_reference, owner_dialog_id, video_size->size_, DcId::create(dc_id),
                                   get_sticker_format_photo_format(sticker_format));
         }
       }
diff --git a/td/telegram/MessageExtendedMedia.cpp b/td/telegram/MessageExtendedMedia.cpp
index fdf93cd5b..b085bb02d 100644
--- a/td/telegram/MessageExtendedMedia.cpp
+++ b/td/telegram/MessageExtendedMedia.cpp
@@ -35,8 +35,8 @@ MessageExtendedMedia::MessageExtendedMedia(
       dimensions_ = get_dimensions(media->w_, media->h_, "MessageExtendedMedia");
       if (media->thumb_ != nullptr) {
         if (media->thumb_->get_id() == telegram_api::photoStrippedSize::ID) {
-          auto thumb = move_tl_object_as<telegram_api::photoStrippedSize>(media->thumb_);
-          minithumbnail_ = thumb->bytes_.as_slice().str();
+          auto thumbnail = move_tl_object_as<telegram_api::photoStrippedSize>(media->thumb_);
+          minithumbnail_ = thumbnail->bytes_.as_slice().str();
         } else {
           LOG(ERROR) << "Receive " << to_string(media->thumb_);
         }
diff --git a/td/telegram/StickersManager.cpp b/td/telegram/StickersManager.cpp
index 4dcef5d8a..b99f125d4 100644
--- a/td/telegram/StickersManager.cpp
+++ b/td/telegram/StickersManager.cpp
@@ -2992,10 +2992,10 @@ std::pair<int64, FileId> StickersManager::on_get_sticker_document(tl_object_ptr<
   string minithumbnail;
   auto thumbnail_format = has_webp_thumbnail(document->thumbs_) ? PhotoFormat::Webp : PhotoFormat::Jpeg;
   FileId premium_animation_file_id;
-  for (auto &thumb : document->thumbs_) {
+  for (auto &thumbnail_ptr : document->thumbs_) {
     auto photo_size = get_photo_size(td_->file_manager_.get(), PhotoSizeSource::thumbnail(FileType::Thumbnail, 0),
                                      document_id, document->access_hash_, document->file_reference_.as_slice().str(),
-                                     dc_id, DialogId(), std::move(thumb), thumbnail_format);
+                                     dc_id, DialogId(), std::move(thumbnail_ptr), thumbnail_format);
     if (photo_size.get_offset() == 0) {
       if (!thumbnail.file_id.is_valid()) {
         thumbnail = std::move(photo_size.get<0>());
@@ -3007,17 +3007,17 @@ std::pair<int64, FileId> StickersManager::on_get_sticker_document(tl_object_ptr<
       }
     }
   }
-  for (auto &thumb_ptr : document->video_thumbs_) {
-    if (thumb_ptr->get_id() != telegram_api::videoSize::ID) {
+  for (auto &thumbnail_ptr : document->video_thumbs_) {
+    if (thumbnail_ptr->get_id() != telegram_api::videoSize::ID) {
       continue;
     }
-    auto thumb = move_tl_object_as<telegram_api::videoSize>(thumb_ptr);
-    if (thumb->type_ == "f") {
+    auto video_size = move_tl_object_as<telegram_api::videoSize>(thumbnail_ptr);
+    if (video_size->type_ == "f") {
       if (!premium_animation_file_id.is_valid()) {
         premium_animation_file_id =
             register_photo_size(td_->file_manager_.get(), PhotoSizeSource::thumbnail(FileType::Thumbnail, 'f'),
                                 document_id, document->access_hash_, document->file_reference_.as_slice().str(),
-                                DialogId(), thumb->size_, dc_id, get_sticker_format_photo_format(format));
+                                DialogId(), video_size->size_, dc_id, get_sticker_format_photo_format(format));
       }
     }
   }
@@ -3572,12 +3572,11 @@ StickerSetId StickersManager::on_get_sticker_set(tl_object_ptr<telegram_api::sti
 
   PhotoSize thumbnail;
   string minithumbnail;
-  int64 thumbnail_document_id = 0;
-  for (auto &thumb : set->thumbs_) {
+  for (auto &thumbnail_ptr : set->thumbs_) {
     auto photo_size =
         get_photo_size(td_->file_manager_.get(),
                        PhotoSizeSource::sticker_set_thumbnail(set_id.get(), s->access_hash_, set->thumb_version_), 0, 0,
-                       "", DcId::create(set->thumb_dc_id_), DialogId(), std::move(thumb),
+                       "", DcId::create(set->thumb_dc_id_), DialogId(), std::move(thumbnail_ptr),
                        get_sticker_set_thumbnail_format(sticker_format));
     if (photo_size.get_offset() == 0) {
       if (!thumbnail.file_id.is_valid()) {
@@ -3587,9 +3586,6 @@ StickerSetId StickersManager::on_get_sticker_set(tl_object_ptr<telegram_api::sti
       minithumbnail = std::move(photo_size.get<1>());
     }
   }
-  if ((set->flags_ & telegram_api::stickerSet::THUMB_DOCUMENT_ID_MASK) != 0) {
-    thumbnail_document_id = set->thumb_document_id_;
-  }
   if (!s->is_inited_) {
     LOG(INFO) << "Init " << set_id;
     s->is_inited_ = true;
@@ -3599,7 +3595,7 @@ StickerSetId StickersManager::on_get_sticker_set(tl_object_ptr<telegram_api::sti
       s->minithumbnail_ = std::move(minithumbnail);
     }
     s->thumbnail_ = std::move(thumbnail);
-    s->thumbnail_document_id_ = thumbnail_document_id;
+    s->thumbnail_document_id_ = set->thumb_document_id_;
     s->is_thumbnail_reloaded_ = true;
     s->are_legacy_sticker_thumbnails_reloaded_ = true;
     s->sticker_count_ = set->count_;
@@ -3646,10 +3642,10 @@ StickerSetId StickersManager::on_get_sticker_set(tl_object_ptr<telegram_api::sti
       s->thumbnail_ = std::move(thumbnail);
       s->is_changed_ = true;
     }
-    if (s->thumbnail_document_id_ != thumbnail_document_id) {
+    if (s->thumbnail_document_id_ != set->thumb_document_id_) {
       LOG(INFO) << "Thumbnail of " << set_id << " has changed from " << s->thumbnail_document_id_ << " to "
-                << thumbnail_document_id;
-      s->thumbnail_document_id_ = thumbnail_document_id;
+                << set->thumb_document_id_;
+      s->thumbnail_document_id_ = set->thumb_document_id_;
       s->is_changed_ = true;
     }
     if (!s->is_thumbnail_reloaded_ || !s->are_legacy_sticker_thumbnails_reloaded_) {