nine patch slice is px? percent?
passible change that 512px X 512px => 80px X 80px ?
BABYLON.GUI.Image.STRETCH_NINE_PATCH: Scale the image using a nine patch technique. You have to either define the sliceLeft, sliceRight, sliceTop and sliceBottom properties or store data into your image (in the first and last rows and columns) and call image.populateNinePatchSlicesFromImage = true to read that data. Demo here -