Training OpenCV for facial detection

I've been working on creating a training database of faces for OpenCV. I've acquired over 8 GB of faces. But, things are going slowly. I've been using GIMP to view the faces and determine the ROI, but its a slow process. Also, GIMP doesn't let me automatically specify a ROI. I can get the TL corner of a ROI but I have to manually post-process to get the width and length. My current method is slow, tedious, and error prone.

I'm considering making my own tool which can ouput a input database in a format that OpenCV can use. I'm going to try to do this in GIMP. But, if I can't, then I'll do something with PIL or HighGui in OpenCV.