any ideas how to optimize this?

any ideas how to optimize this?

Hello,
I am new to this forum, as to jquery or html. I was learning beginners material and at the same time trying to make some basic animation. I created an object array with 16 objects and animated them. But now I see if I make animation loop at 30fps my cpu info shows like 18-20% of cpu load. this is just the beginning of my idea, and when I will fill it with all the objects to render, it will be consuming way more of cpu resources... so maybe I am missing something here? maybe I should be using png transparent pictures instead of rendering that many objects, or something else? this is a index.html I am working on:
www.narbuto.lt/indel.html
I would be very grateful if anyone could comment about my page source code
Thanks