Reduce a presentation’s file size in Keynote on Mac
If your presentation includes image, audio or video files, you can reduce its file size to make it easier to send, post or share.
If you don’t want to permanently change your original presentation, you can save a copy of it with a smaller file size instead.
Choose File > Reduce File Size (from the File menu at the top of the screen).
Select the adjustments you want to make:
Scale down large images: Images are scaled to the resolution used in the presentation while preserving visual quality. For example, if you added a photo to your presentation and resized it to be smaller, selecting this option removes the unused image data.
Note: Whether or not you select this tick box, if an image is in a format that can’t be viewed on iPhone or iPad, it’s automatically converted to a format that can.
Remove trimmed parts of movies and audio: If you trimmed the start or end of movies or audio clips (using the controls in the Format sidebar), the trimmed portions are deleted.
Most compatible (H.264): Movies in your presentation are converted to H.264 format, which plays on most iOS devices, iPadOS devices and Mac computers.
High efficiency (HEVC): This format option appears only if you’re using macOS 10.13 or later and your Mac supports hardware HEVC encoding. Movies in HEVC format have the best quality at the smallest file size, but they can be played only on devices with iOS 11, iPadOS 13, or later, and Mac computers with macOS 10.13 or later.
If you’re using macOS 10.13 or later and Keynote 8.0 or later and you select this format, you can later add HEVC files to the reduced-size presentation or copy. For more information about HEVC, see this Apple Support article.
Note: H.264 and HEVC don’t support alpha channels, so transparency is converted to a black background.
Preserve original format: This option retains the current movie formats. In this case, any movies in formats incompatible with iOS or iPadOS aren’t optimised and therefore don’t play on iOS or iPadOS devices.
Movie Quality: Set the maximum resolution for movies. Movies with a resolution smaller than the maximum aren’t scaled up.
Click one of the following buttons to apply the adjustments:
Reduce this File: Applies the settings to the original presentation.
Reduce a Copy: Applies the settings to a copy of the presentation and preserves the original presentation. Enter a name for the copy of the presentation and choose where to save the copy, then click Save.
Note: It’s possible to choose a combination of options that make the file size larger.