http://gimpchat.com/viewtopic.php?f=23&t=13220&hilit=dollface
I wrote a tutorial on the Gimpchat forum a couple of years ago describing how I make the dollface images I use here on deep dream. The tutorial is written for Gimp 2.8 and the version most users use now is 2.1, but the process is so similar you can just follow along anyway. Further down in the tutorial thread there is a very helpful tip from user Nidhogg where he shares his filter settings for making the eyes, so that's well worth checking out.