Oh, OK. Regarding the background: That works, and you do the same thing in GIMP but that doesn't handle transparency. In GIMP there's the Color to Alpha tool which is pretty much magic.
Say you have https://this.is-a-professional-domain.com/4Hhtqcf.jpg and you want that glow on a transparent background. In GIMP, I'd select the chip, Select>Invert, Color>Color to Alpha and it would just work. I tried to do it in Photoshop and couldn't figure it out.