How to Create semi-transparent overlays in iMovie in Mac OS X

Learn how to use Seashore to create a 32-bit semi-transparent image and then use that image as an overlay to point out or highlight something in your iMovie video. It's easy! So easy, in fact, that this home-computing how-to from MacMost can present a full overview of the process in about 4 minutes. For more information, including detailed, step-by-step instructions, watch this Apple lover's guide.