Since I really believe that not enough is done with cow print clothing in here (LOL) I decided to post a tutorial on how to make fur with Photoshop.
I am not familiar with Gimp but for those of you who use it you most likely will be able to find similar functionality in that software.

1) First, find or make an image you want to turn into fur. In this case I put some simple black splotches on a white background. I live in farm country and have a fondness for Holsteins LOL.



2) Next, add "Noise" to the image.





I suggest you do it monochromatically or else you might end up with a weirdly holographic end product (which may be fine if that is what you are going for but generally won't simulate animal fur well).

You will also have to play with the distribution and the amount until you get the effect you are looking for.

3) Now you want to blur the noise using "Motion Blur" to create the hairs that fur is made up of.





As with the Noise, you will need to play around with the parameters such as direction and distance until you get the effect you are looking for.

4) By now the image should be looking pretty furry. You can then tinker with the coloring to brighten it up if you like, as adding noise and blurring it will mute the colors a bit.




Happy furring!