Optimize performance in your iBooks Author books
In iBooks Author, you can create media-rich books that are compatible with Apple Books. Learn how to optimize the performance of large books, which can take a long time to preview, export, or publish.
Work with images
Whenever possible, use JPG files for opaque raster images and PNG files for transparent raster images.
Resize, crop, and rotate images to the desired size and rotation before you import them into iBooks Author.
If you need to use high-resolution images in your book, wait to add them until your book is almost finished.
Image size depends on the type of display your readers use. Learn how to optimize books created with iBooks Author for devices with Retina and non-Retina displays.
Work with movies
Trim your movies to the desired length before you export them for use in iBooks Author.
Learn more about working with movie files in iBooks Author.
Organize your book into chapters with sections. Avoid creating large sections or chapters.
Avoid adding too many widgets to a single page.
The Book Store on Apple Books accepts books up to 2.0 GB for publication. Although you can distribute larger books for free through other channels, keep the size down for best results and to avoid performance issues.
As an alternative to using the Preview function in iBooks Author, you can export your book as an .ibooks file and open it on your Mac. To see the file on another device, export the .ibooks file to iCloud Drive, or export the file to your Mac and use AirDrop to send it to another device.