This is an app that Harry McCracken talks about in Time Magazine, April 8, 2013. Ask the Expert.
"Photoshop Touch($4.99, iPhone, Android). The phone-size edition from the most famous name in image-editing software retains a startling percentage of the desktop version’s power. You can crop, re size and retouch photos and apply fancy filters to make your pictures look like watercolor paintings or pencil sketches."