I’ve put down few steps to make your own Hackergotchi in less than 10 minutes. I’ve used the GIMP. Nevertheless, it should be easy to use these steps in other Image Editing Softwares as well. (Click on the thumbnails to view full size)
1) Find a good photo of yours, preferably with a plain background. If you can’t find one such photo, you’ll realize the power the Fuzzy Select tool (also called Magic Wand by some others). We start with this photo (Google was generous enough to find a picture of a baby this purpose 
).
2) Now, use the Fuzzy Select (Magic Wand) Tool. Play around with the option called threshold. You always have Ctrl+Z to go back. Select any region which does not fall under what you define as Face and keep deleting them. ( Process can be made faster by holding down the Shift key while selecting. This will keep adding all the selections)
Be sure to have the Feather Edges option checked. We don’t want rough edges.
3) Now use the Free Select Tool (Lasso) to select and delete the areas that are still left over. Magnifying the image will be of great use to remove unwanted areas very close to the face. Edges of the selection come out better when the image is magnified.
There, we have the face. To get better edges, we could do a few more things.
4) Select the white region (area other than the face). This can be done by clicking on the white area with the Fuzzy Select Tool.
Now, do Select -> Grow.. and grow the selection by 1 px. Delete.
5) The edges should be better now. Select the white area again using the same method described above. A good idea is to make this area transparent. Select Colors -> Color to Alpha. If you can’t find this under the Colors Menu search somewhere else. Basically, we want to make the white region transparent. Select White in the Color to Alpha dialog box and press OK. We just have to drop a shadow and we’re done.
6) To add a shadow, select the face. For this, select the transparent area using the Fuzzy Select Tool just as we did for the white area. Invert this Selection by doing
Select -> Invert or Ctrl + I. We now have the face selected. Now select
Filters -> Light and Shadow -> Drop Shadow. Again, if you can’t find this option, search somewhere else.
We’re done!
