Custom Boot Splashscreen

[Jeppi]

Hi,
I want to display a .gif while the Raspberry is booting up. I tried this guide (https://yingtongli.me/blog/2016/12/21/splash.html) but it didn’t work.
So now I’m trying to solve this with plymouth, but for some reason I can’t even use the default-themes. Even after selecting any plymouth theme nothing changes. I am using Jessie Lite.

So does anyone know a way to display a .gif during the boot-up?

Thanks!