How to make a photo grungy in GIMP
This is a very simple method to making photographs grungy, but its also a good technique to have handy in your mind for any post-processing you might do in the future!
Zoom Blur Effect in GIMP – GIMP Tutorial
If you don’t have a zoom lens or you’d like to manipulate a certain image in this style then this tutorial for GIMP should help you achieve a similar effect!