Cant import 16 bit .png splatmap in landscape>manage. "File type not recognized"

Hi, I keep getting an error when trying to import splat maps.

I’ve tried 8/16/32 bit .png and .raw but it keeps giving an error… it always previously let me import them the old way in UE4 by right clicking the layer>import from file but now it doesn’t work anymore.

I’ve seen other people make it work in tutorials but no format will come in for me and it gives the little red exclamation error.