  The excessive use of images in social networks, government databases, and
industrial applications has posed great privacy risks and raised serious
concerns from the public. Even though differential privacy (DP) is a widely
accepted criterion that can provide a provable privacy guarantee, the
application of DP on unstructured data such as images is not trivial due to the
lack of a clear qualification on the meaningful difference between any two
images. In this paper, for the first time, we introduce a novel notion of
image-aware differential privacy, referred to as DP-image, that can protect
user's personal information in images, from both human and AI adversaries. The
DP-Image definition is formulated as an extended version of traditional
differential privacy, considering the distance measurements between feature
space vectors of images. Then we propose a mechanism to achieve DP-Image by
adding noise to an image feature vector. Finally, we conduct experiments with a
case study on face image privacy. Our results show that the proposed DP-Image
method provides excellent DP protection on images, with a controllable
distortion to faces.
