Instagram is currently experiencing major problems with its instagr.am URL shortener, which has resulted in photos being unavailable across Twitter and Facebook. Substituting the full Instagram domain (i.e.: instagram.com/p/xxxx) seems to be a temporary fix, but the massively popular photo app utilizes the shortener by default — meaning any photo you share to social networks can't be viewed at the moment. We've reached out to Instagram for comment on the glitch and will report back when we hear more.
Update: Photo links appear to be working again — at least intermittently. Explaining the temporary disruption, a Facebook spokesperson told The Verge, "We were making improvements to our domain management, and there were a few technical issues in the migration."