It's almost invisible against your background photo, but at the very bottom, there are a bunch of dots just like on the home screen, except the rightmost dot is

It's almost invisible against your background photo, but at the very bottom, there are a bunch of dots just like on the home screen, except the rightmost dot is a camera icon. It's not a button you can tap, it's an indicator of what is on the page to the right. It's the same on my 7. World's most subtle indicator.