Converting Gimp brushes and Gimp patterns into Photoshop brushes and patterns is fairly simple, open the Gimp brush or the Gimp pattern as an image in Gimp, export as png, open in Photoshop, define the brush or pattern as a brush or pattern. Gradients, however; you cannot save then as a regular graphic and the Gimp .ggr files are unrecognizable by Photoshop. Gimp has this feature addon called "sample gradient along a path" which I used to make some of the gradients. I downloaded a few years ago a massive 300 gradient pack for Gimp. How do I turn these into Photoshop Gradients?