Hello HR Manager,
I read your job post carefully and you want to build an wallpaper which have GIF image and it will be change automatically.
I am an experienced android developer , I can build your application within a week.
if I build your app , I will use Glide library which support GIF image and other functionality,
you can also made your app as dynamic, that you change your GIF image in website , it will automatically update your wallpaper, so that your wallpaper will be updated and realistic.
with best regards,
Anwar
Bangladesh