Reader Eric Cantrell suffers from overstuffed Keynote presentations. He writes:
I routinely create Keynote presentations for work and when I insert images and movies, the resulting files are so huge that I can't send them via email. Is there some way that I can trim them down?
I can offer a couple of suggestions.
First, examine the file format and resolution of your movies and images. If you're using standard QuickTime .mov files and large resolutions (1080p, for example) you should instead encode your movies in H.264 at a lower resolution. Likewise, if you can get away with JPEG images rather than PNG or TIFF, you'll save some space.
Fortunately, you can deal with this after the fact. You do it this way.
Open your presentation in Keynote and duplicate it. This prevents you from mucking up your original file. With the duplicate open choose File > Advanced > Optimize Movies for iOS. This will convert any movies in the presentation to H.264 if they're not already in that format.
Next, return to the File menu and choose Advanced > Reduce File Size. Keynote will cogitate for a bit and then tell you how much space it will save by reducing image resolution and removing unused parts of audio and video files. Click Convert and your presentation will be slimmed.