"ImageMagick (IM) is a command-line graphics creation and editing application. In a previous article we used it to add text and frames to images, and for other basic image manipulation. In this article we'll use the ImageMagick suite of commands to create a multi-image mosaic, draw some basic shapes, and create 3D logos.
"Pasting one image over another is known as superimposing. Using this technique we can turn the hard-corners of an image into rounded borders--or any other shape, for that matter--by simply superimposing pre-fabricated transparent curved corners onto the image..."
