Mikko Koppanen has another example of image manipulation in PHP through Imagick to create dynamic thumbnails of your images.

Today's example is about making pretty thumbnails by combining a drop-in shadow with round corners. The image is first scaled down to create a thumbnail. [...] The next step is to round the corners of the image. [...] The final step is to create the drop-in shadow and composite the thumbnail over it.

Both the code block to create the thumbnail and a before and after image to show how it translates in the post.