Пробуем разные типы картинок
как то png jpg gif
и делаем вывод
Foldergallery does not works with png & gif
The same was with zgallery, but we partly fix this. Now zgal shows all king of files, only doe not generate thumbs.
- Zgallery shows png & gif, but transparent & background black, should be #f6f6f6
Style as mozaik is suit as more. Background also.