Customers with CDN access now have the option to upload the media included in notifications, rather than entering a URL. This is the easiest way to include rich media in your notifications, especially if you don’t have another way to host media yourself.
A CDN supports optimized delivery of rich media to mobile devices across a global audience. It dynamically caches the media in critical locations across the globe to minimize download times, even across lower-bandwidth cellular connections.
We currently recommend using file sizes around 1MB to ensure successful delivery of hosted media. Our media hosting solution does not store files over 2MB at this time. Although iOS 10 supports theoretical maximum file sizes that are much higher, in practice we have not yet seen the platform successfully download and display files anywhere near those limits.
Images: JPEG, GIF, PNG
Audio: AIFF, WAV, MP3
Contact Support if you are interested in enabling CDN media hosting.