I exported a simple Animated PNG and placed it in Adobe Muse. Performed the same step with an Animated GIF. The Animated GIF worked but the PNG did not. Not sure if there is a lack of support for Animated PNG with Adobe Muse. Help!
This is likely a browser issue, or an issue with how Muse handles APNGs, which are a new format. Current support is not great: http://caniuse.com/#feat=apng
Animated GIFs, on the other hand, are almost older than me.