I misunderstood your original comment. The reason why there were 500 requests is because I was showing a background full of creepyfaces. It made the site look much nicer but it turns out it didn't scale very well.
Turns out the other heads were removed so it's not doing 500 requests anymore. So where does that leave us? Should we keep arguing over the original situation?
https://gist.github.com/4lejandrito/6d4f903e0a692b87344e8600...
The resize function only resizes the first time and uses a cached version of the image after that.
I checked the server and the CPU is not too high so I think it must be HTTP as parent pointed out.