Although GIMP does not include a diamond texture option, as of June 2012, experiment with digital patterns, paint brushes and filters to superimpose a sparkling effect.

How to Make Texture Tiles Seamlessly in GIMP. You can use the free graphic editing program GIMP to make patterns and textures for backgrounds in Web design and other digital projects.

Some of GIMP’s greatest assets are the plug-ins and scripts created by numerous independent programmers. We'll find some good ones for you.