TouchRetouch is a magical little app which has found a place in my top photography apps folder on the iPad. Basically it allows you to erase unwanted objects from your photos, but the magic comes when it seamlessly fills in the space afterwards.
This kind of ability was until very recently only available in mainstream software costing a LOT more than the 79c this set me back on the App Store. Using the intuitive finger swiping which iPad apps offer (so much more natural than a mouse) you simply paint onto the photo in the area you want to disappear, and then pressing the Go button brings in a delightful little fade out of the unwanted object, magically replaced with a seamless rendering of elements drawn from the surrounding areas of the photograph.
Options to save your edited image at various resolutions mean that it is easy to output just say an iPad (1 or 2) resolution final image of 1024×768, great for uploading to any of the social media sites supported or just saving on your precious storage capacity.
If you do any image post processing on your iDevice then this is an essential app which will help you create far more polished final results. There is an HD version for the iPad and also a free version which lets you use all the features but watermarks the images.