In implementations of determining user segmentation based on a photo library, a device maintains digital images in the photo library, as well as metadata associated with the digital images. The device includes a segmentation module implemented to determine characteristics about a user of the device by analysis of the metadata of the digital images. The segmentation module can determine a segmentation based on the characteristics determined about the user. The segmentation includes one or more segments that each represent a generalized aspect of the user, where a generalized aspect is attributable to multiple people and anonymity of the user is maintained. The segmentation module can associate an anonymous identifier with the segmentation effective to maintain the anonymity of the user and privacy of the metadata. The segmentation and the anonymous identifier can then be communicated to a marketing system that generates personalized marketing messages based on the segmentation.