If it's not working when you're saving it to the original rock texture file, I'd highly recommend moving your texture's code to its own document and saving it as a .material file into your materials folder, and then see if it works. Also make sure that the image is .jpg so it matches up with the code to avoid further problems.
And a little tip, as long as the material file and the image itself exists somewhere within FH's folders on your computer, it doesn't matter where exactly they are. Just for future reference.
