The photo app hasn’t too many filters in various styles, but if you want to convert your photo into a ketch or cartoon image, the photo app XnSketch will help you.
XnSketch is an easy-to-use photo app developed by XnView, and designed for both iPhone and iPad. The iOS app has an intuitive and simple user interface, just tapping the two icons in the left upper corner you can import your photos or take photos directly in the app for further editing, and the photo app features 20 built-in sketch themed filters in order that you can convert your photos into various stretches or cartoon images, while detailed adjustment settings allow you to create one-of-a-kind photo effects. Of course, you can also easily share your masterpieces with friends via Email, Facebook, Twitter, Flickr, Tumblr and more.
XnSketch with a size of 6.0 MB is compatible with iPhone (optimized for iPhone 5), iPod touch and iPad running iOS 5.0 or later. The iOS app is free for a limited time at present. If you’re interested, jump to App Store for more details.