Launcher Icons not changing (ubuntu 16.04)

I've been trying to change my icons for days. Some of them change within my file system, but never the 'bigger' stuff like the launcher. I boot up unity tweak tool and change it in icons but the launcher icons never change.

I really want to change the default launcher icons, is there perhaps another way of doing this, or something else I can do with unity tweak tool?

(I have tried restarting and reinstalling unity tweak tool)

Thanks!