If you want to get a background on how FaceShape works, you can check out our tech blog. The one thing you need to know is that, our algorithms require a lot of images in order to be accurate.
When you upload a picture using the FaceShape finder tool (for example: on the homepage), we upload that picture for analysis.
We don't sell those pictures. We don't share it with external entities or humans, except for data labelling purposes. Data labelling is the process in which a human takes a look at a picture and manually labels it (ex: says what face shape it is). We don't show those pictures to other members of FaceShape community unless you create a public post which includes those pictures.
If you want, you can opt out and we won't upload your pictures, but keep in mind that this will prevent us from improving our algorithms for you and people who have similar face shape as you.