added file filter string for PNG
added file filter string for PNG

nakijun/vtp,nakijun/vtp,seanisom/vtp,nakijun/vtp,nakijun/vtp,nakijun/vtp,seanisom/vtp,markraz/vtp,markraz/vtp,seanisom/vtp,seanisom/vtp,markraz/vtp,seanisom/vtp,markraz/vtp,markraz/vtp