Amount of Navigation tabs

Is there a limit on what actually shows in the navigation, if so how could i change it to add more from the little green drop down thingy..sorry dont  no what it is called lol...as you can see my photos and vids are super stretched, or if there is another way to sort this so everything looks in proportion :-)

You can change the number of navigation menu items before the "more" link is displayed from administration, settings, other.

Excellent, Thanks :-)