What was the cause of my cell phone's freeze-up?

I went to the Tokyo Dome to watch the baseball game, Giants vs. Swallows with my friend yesterday.

At the present time, Giants is 4th, Swallows is 3rd in the Central League and both of them are MUCH distant from 1st and 2nd teams. So I thought spectators were few but not really.

Giants won 2 -1.

My friend brought and gave me a cheer megaphone of Giants. I left my own one at my parent home, so thank you!

I'm a Giants' fan but she is a Swallows' fan, so she also brought a megaphone of Swallows and cheered with it. I took a picture of her cheering with the megaphone by my cell phone to put it on this blog, but my cell phone froze up when I tried to save the pic. Cell phone freeze up? It's the first experience and I've never heard freeze-up of cell phone. Any problem with her pic???