Apple's iPhone 4S benefits from an 8Mp camera and the previous versions of Apple's smartphone have also come with decent photography equipment, which means using your smartphone to capture pictures has become the norm. But once you've taken plenty of shots, why not have some fun with them? There are hundreds of apps that allow you add unusual features to your photos from adding colour to one specific area or allowing you to switch faces in an image. Here's five of our favourite free iPhone apps for adding unusual features to your photos.

Photo Booth for Free

If you were a fan of Photo Booths when you were younger, you'll love this app that not only lets you turn existing images snapped on your iPhone into strip photos but also lets you add fancy dress such as hats, glasses and moustaches to your photos.

Color splurge

Give you photos an unusual look with Color Splurge, which lets you 'paint' a specific part of your photos a particular colour so it stands out.

Pic Collage

Make a collage of all your favourite photos using this app. You can even rotate and resize images once you've placed them on your collage.

Face Bender Free

Give the subjects of your photos an 'interesting' new look by warping, twisting or stretching their faces using Face Bender Free. You can add unusual eyes, hats and other add-ons to your photos.

iSwap Faces Lite

Switch two faces on an image quickly and easily with this free app.