So you propose that the designer of the webpage took a static image, from which he created several gif animations, Then laid it over the original image?
It sounds like a lot of effort to achieve the effect. I have checked the HTML portion of the webpage and noticed that the gif has been laid over the original image in three different locations.
I have never seen that technique being applied before.
Videos and GIF animations commonly used as backgrounds, but this solution seem truly unique to me.
What would be your workflow to create something like that?