Mounted images is a really bad way to do hats. They lag horribly when you start mounting loads of them for different hats, bodies, armour pieces and whatnot - that's the entire reason they were replaced with the m.dts method in this version of Blockland. Unfortunately, this cuts out the possibility for custom hats. I suggested a better method a while back (which could utilise the avatar menu and custom colours, allowing custom body parts as Add-Ons) but it was basically ignored.