In the game editor, I take a screenshot of Arthas's hammer. In GIMP, I flipped it so it's aligned. Using the selection tool, I removed the background, making it black, and added the blue glow. Then, on a top layer, I added shading, highlighting, and lighting to make the hammer more visible. Finally, on another layer, using the brush, I manually added the glow surrounding the hammer, the white, and the magenta.