How to: Prepare an image for laser engraving using GIMP/ INKSCAPE/ K40 WHISPERER - YouTube
Engraving
Create engraving in GIMP/Inkscape - Graphic Design Stack Exchange
Prep a Photo Engrave in Gimp – Glowforge
GIMP Tutorial: Preparing A Photograph For Laser Engraving - YouTube
How to Create a Custom Laser Engraved Painted Canvas - EnduranceLasers
0509 Gimp (Photo to Screen Print and or Laser engrave) - YouTube
Laser Engraver Guide
Practicing on a piece of granite with my k40 laser, I used Gimp and Inkscape to do some dithering as well as greyscale, it turned out okay but I'm not to say
Create engraving in GIMP/Inkscape - Graphic Design Stack Exchange
Tinkershop Tutorial: Photo Engraving With Gimp - YouTube
Prep a Photo Engrave in Gimp – Glowforge
GIMP 2.8 Create an Engraving within an Image Tutorial - YouTube
Convert an Image to a Vector Graphic for Laser Cutting - Tutorial Australia
Laser Engraver Guide
How to Create Engraved Text in GIMP – Better Tech Tips