Flic
It doesn't matter if you've got a 128GB iPhone 6 Plus or an 8GB iPhone 4 — odds are you have some photos in your Camera Roll you could do without. Flic makes it easy to get rid of them, by prompting you to go through a whole month's worth of photos at a time, swiping right if you want to keep the current photo and left if you don't. There's an undo button in the corner for wayward swipes — the photos are only permanently deleted after the whole month's been sorted through and you've given them one last glance — but the simple interface makes clearing up your camera easier than ever.
