Adobe Photoshop is the industry leader when it comes to PC and Mac image editing software. Image editing is not something readily associated with mobile devices such as the iPhone and iPad, but Adobe Photoshop Express is a free app available for Apple devices that enables you to edit and share images from your idevice.
The app couples up with Photoshope.com. Adobe's online photo editing and sharing site, and makes it possible to not only edit images on your idevice, but also share them online. There are a wide range of basic editing tools available such as cropping, straightening, flipping and rotating, and it is also possible to adjust colour levels, saturation and other image settings.
There are also a number of filters available - such as sketch, software focus, and sharpen - as well as a range of special effects such as vibrant, pop, vignette blur and many more. Borders can be added to images, and there are a large number to choose from.
The mobile version of Photoshop was never going to be a replacement for the desktop version of the software, but for a mobile app, it is incredibly impressive. There are just enough options available to make this a valuable tools without it becoming overwhelming or unwieldy.