Do not create thumbnail info if there is no thumbnail

lib/structs/events/common.cpp

@@ -64,8 +64,10 @@ to_json(json &obj, const ImageInfo &info)
         obj["w"]              = info.w;
         obj["size"]           = info.size;
         obj["mimetype"]       = info.mimetype;
-        obj["thumbnail_url"]  = info.thumbnail_url;
-        obj["thumbnail_info"] = info.thumbnail_info;
+        if (!info.thumbnail_url.empty()) {
+          obj["thumbnail_url"]  = info.thumbnail_url;
+          obj["thumbnail_info"] = info.thumbnail_info;
+        }
         if (info.thumbnail_file)
                 obj["thumbnail_file"] = info.thumbnail_file.value();
 }
@@ -94,8 +96,10 @@ to_json(json &obj, const FileInfo &info)
 {
         obj["size"]           = info.size;
         obj["mimetype"]       = info.mimetype;
-        obj["thumbnail_url"]  = info.thumbnail_url;
-        obj["thumbnail_info"] = info.thumbnail_info;
+        if (!info.thumbnail_url.empty()) {
+          obj["thumbnail_url"] = info.thumbnail_url;
+          obj["thumbnail_info"] = info.thumbnail_info;
+        }
         if (info.thumbnail_file)
                 obj["thumbnail_file"] = info.thumbnail_file.value();
 }