My Face Diary for iPhone is a slim and powerful iPhone app to help you capture and organize your daily portraits. You could easily modify your photos by choosing decorations, applying special effects, or just draw anything you want on them!
You could use it to share your best photos or drawings with your best friends, via Facebook, Twitter, Flickr, and other social networks.
The official website is : http://www.myfacediary.com/
Unretiner is a very useful tool for iOS art production. I found it’s much more convenient than shrinking and resaving image from Photoshop (I often forgot to resize the shrinked image back!)