Can I set a default "About Me" photo?
Solution 1:
Yes, simply place an image file named .face in /etc/skel.
sudo cp new_photo.jpg /etc/skel/.face
NOTE: Not all image formats will work, so stick to PNG and JPEG.
The /etc/skel directory contains files and directories that are automatically copied over to a new user's home directory when the user is created.
The name of the directory skel is derived from the word skeleton, because the files it contains form the basic structure for users' home directories.
Source: http://www.linfo.org/etc_skel.html