Just throwing this out there:

Would it be possible to have a script that crawls through images on Commons, detects faces in the images, and embeds the x,y position of the face(s) into the File page of the image (or into the Exif data of the image) (and makes this information available via the API)?

For a little context -- in our mobile apps, we'll be featuring images related to the article that the user is browsing; however, the way that we're cropping the images sometimes has the side effect of cropping out the face of the subject (when the face is far from the center of the image). Even though we can do face detection locally on the user's device, it can be a bit slow and a bit intensive. It would be great if this task was offloaded, and the face position was returned right along with the image itself...

-Dmitry