You Doodle is a free drawing application for iOS devices. You can draw directly on your device or on top of one of your photos. You Doodle allows you to create layers, merge backgrounds, draw in colors, add shapes, and more, making it a comprehensive application that unfortunately has many locked features that require a paid upgrade.
You Doodle does not have instructions after sign on, which would be useful for such a feature-rich application. While it is advertised as a drawing application, it also has features for creating layers, adding backgrounds, and using shapes. You can customize to almost any color, alter the size of the brush, and upload directly to Twitter, Flickr, Dropbox, and even your printer. Some of the app's features require a paid upgrade, and the application doesn't tell you that it requires the upgrade until after you add the art, which is frustrating to those that have taken their time to draw or edit, only to find that their work can't be saved without the upgrade. Luckily the advertisements in You Doodle are not a significant distraction, so working with the app is fairly easy.
There are many drawing applications available for iOS devices, and because many people work with small screens, the usefulness of these applications is limited. But You Doodle is still a fairly solid, free option, and while it can use better instructions and more warning about the paid features, it is not a bad tool to have on your iOS device.