DreamGif

Simply choose a gif from your phone storage, select a background colour and how big you want it to be. The gif will loop indefinitely next time your daydream starts.

If you are new to Daydreams:
A daydream is basically a screensaver which you can set to come on when your phone is charging and idle. To enable it, open this app, then open the System Daydream Settings via the overflow menu and choose DreamGif from the list.

Please see https://plus.google.com/u/0/communities/113955537219140914914/stream/b21acf1c-3baa-4dc3-8e76-33ebfb476553 for changelog archives and to ask any questions.