論文アブストラクト：We report on a design-led study of the photographic representation of self and family on Facebook during and after becoming parents for the first time. Our experience-centered, research-through-design study engaged eight participants across five UK homes, in a month-long deployment of a prototype technology -- a design research artifact, Admixed Portrait, that served to prompt participant reflection on first-time parenthood. In addition to pre- and post-deployment interviews, participants kept diaries capturing personal reflections during the deployment, on daily social media use and interactions with Admixed. Our qualitative insights on social media representations of transitional experience and identity for new parents, reveal how their online 'photowork' related to self-expression and social functioning. We contribute design considerations for developing tools to support photographic expression in social media use, and methodological insights about design-led inquiry for understanding transitional experiences.