Unfortunately, the Kindle platform does not support transparency.
When you upload your ebook to Kindle, any transparent images in your book will be converted to have a white background, which readers will see if they use a dark color scheme:
This is outlined in KDP’s Image Guidelines. (You’ll find the pertinent information at the very end of this page under “Supported input formats.”)
Note that this limitation is specific to the Kindle platform. This means that if you publish on other platforms, like Apple Books, readers will see images with transparency. To view how this looks, you can change Vellum’s Preview to show an Apple Books device, such as iPad or iPhone:
You can learn more about previewing your book in Vellum Help.
Still have questions? Contact us.