Editing a Photo | From ( X by Y ) to ( A by A )

When I upload my Facebook photo there are no requirements on the x and y dimensions of the photo. However Facebook finds a way to insert a 50px by 50px photo that is not distorted into the news feed.

Th开发者_如何学Goe only way you could do this, unless I am mistaken, is by cropping the image so that x and y are equal and then scaling to 50px by 50px.

But I never see any photos with like half a face or off-centered. So how do they determine how to do the cropping. Are they using some sort of face detection algorithm or are users required to to this centering manually?

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When you upload your profile image, you get a link "Edit Thumbnail"

By clicking this link you get a popup that allows you to drag the image around (or scale the image) until you find a position you like.

Although Facebook certainly has the ability to implement the face detection algorithms (they already do e.g. upload a photo and you get asked to tag all the faces), as far as I am aware there is no magic in the profile pictures.

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It's quite easy to scale and crop a photo, so it would be trivial for facebook to create 50x50 thumbnails of peoples faces. However, facebook does have a lot of facial recognition technology as demonstrated by their automatic tagging (they can even tell which face belongs to which friend).

It's pure speculation however I would say there is a good chance the use their technology to crop to peoples faces.