Is it normal for women to flash the camera when taking pictures with their friends?

My friend told me something weird ab his gf he wasnt sure about but i didnt know the answer and was curious so figured Id ask here. When his gf takes pictures with her friends (from the privacy of their own home) somewhat often she will pull out her boobs or pull down her pants and show her butt in some of the photos. When he asks why she just says cause its funny. He says when she shows him the bulk photos with some of those, she never skips over any bc her friends were doing it. But maybe theyre hidden or deleted for that reason. Never thought about doing that as a guy. Is it normal for girls?