NULL/NO DATA values in Displacement Map

I have never actually used external files(my displacement images) in jsfiddle sorry, however, it is basically this exact simple example but using my own DisplacentMap image file and Texture image file for the color. three.js dev template - module - JSFiddle - Code Playground

i included the .png here if youre interested…
(is NoData vs ‘Transparent’ an issue?)

it also has lots of similar questions/answers here: (alpha map as you suggested)

thxColorado_clp