Initial support for this is now in the 'getImageFromPCXWithAlphaBlend(Pcx imagePcx, Pcx alphaPcx, int leftStart, int topStart, int croppedWidth, int croppedHeight)' method in PCXToGodot.cs. It does not yet handle the fact that the alpha files may be smaller than the non-alpha ones, and meant to be repeated across them, beyond that it will stop and not crash if the alpha is smaller, while still applying alpha to the alpha-file-sized area. This is good enough for the menu icon to be alpha, though fleshing that out more fully will be necessary for e.g. the hover state menu icon to be alpha.