Amazfit Watch faces

I edited a file that has animation, just as shown in this tutorial (https://amazfitwatchfaces.com/blog/creating-watchfaces-bin), but when you pack the files it changes the animation images from "png" to ".dat", only the first animation image continues "png". How to solve?! MiBand4

I edited a file that has animation, just as shown in this tutorial (https://amazfitwatchfaces.com/blog/creating-watchfaces-bin), but when you pack the files it changes the animation images from "png" to ".dat", only the first animation image continues "png". How to solve?!