Could have a little higher production values. Like transparent png images.
I will definitely have to check into that, thanks for the tip!
I wish I was more proficient with images etc (and had more time!)...
My son and I built this website
and this java page. We host it on our servers at home

.
We use all open source software.
Once again thanks for the tip!
In the end I guess it doesn't really matter, since the only time you really see the white image borders is when you're dragging some heads onto others forcefully. Even with transparent images, you'll still have gaps between the heads(so they don't sit completely next to each other).
To solve that, you'd need per pixel collision, which might not be something you're familiar with or really care to implement.
Fun though! Glad you have a mix of people in there, and not just one sided.
Here's an idea but one which would require extensive knowledge of working with windows API's... make it a desktop toys application, such that the heads are right on your desktop.
In addition to the gravity, all you'd need are a selection of virtual weapons(like a crossbow that impales and freezes the head on screen) and... well, probably a lawyer because people would be very uptight about such a thing.