creating hose nozzles

I cannot create nozzles in Painter 2020. I follow the directions, and the library shows a blank nozzle. I have saved images (RIFF) that I want to make into nozzles and I'm doing something wrong. I open the nozzle panel, click load nozzle, the menu showing my RIFF files open, I choose the one I want to load, I open it, click add nozzle to library, and a blank nozzle shows up in the library. Help!