Photos won't close

[hedgey1]

Hi
Got my S4 yesterday and already it's got a glitch. When I open/look at a photo in Facebook or the store to its biggest size, I then can't close it back to original without having to shut the phone down and re open the app.
Any suggestions welcome

Hedgey

 

[hedgey1]

You can tell I have had iPhones too long. Just found the return button next to the home key lol doh lol