One of the things I really like about Keynote is its ability to work with images built with vector graphics (including transparency information). The big advantage of vector graphics is that they scale up and down perfectly—typical bitmapped images, such as JPEG or PNG, won’t scale up very well at all.
Sometimes, though, it can be a challenge finding good vector graphics images to use in Keynote. If you’re also a user of OmniGraffle, however, you’ve got a great source right under your nose. Keynote can work with the images on OmniGraffle’s stencils (previously known as palettes). These images are all built with vector graphics, and so they scale wonderfully when used in Keynote.
Usage is as simple as drag-and-drop. First open Keynote and move to the slide where you’d like to use the image. Next switch to OmniGraffle 5 (or most likely any version of OmniGraffle). Then use the Stencils menu to select a stencil set to use, such as Stencils -> Business -> Network. When the stencil set appears, simply drag and drop any image you’d like to use directly from the stencil window and drop it on your Keynote slide.
The dropped stencil becomes an object on your slide, complete with transparency. But the real fun begins when you drag a drag handle—the dropped object will scale up (and down), staying completely crisp the whole time. Because the dropped stencil is an object in Keynote, you can duplicate it, include it in animations, mask it, and perform all other such Keynote object manipulations.
If you find the bundled OmniGraffle stencils too limiting, check out Graffletopia, a third-party site that hosts a large collection of varied stencils. After downloading any stencil from the site, just drop it into your user’s Library -> Application Support -> OmniGraffle -> Stencils folder, and it will be instantly available to OmniGraffle.
I have used this tip many times over the years, most recently in my managing e-mail on multiple Macs Macworld video. The simple animations of POP and IMAP were done in Keynote, but most of the objects were brought in from OmniGraffle.