Proximal splitting algorithms are becoming popular to solve convex optimization problems in variational image processing. Within this class, Douglas-Rachford (DR) and ADMM are designed to minimize the sum of two proper lower semicontinuous convex functions whose proximity operators are easy to compute. The goal of this work is to understand the local convergence behaviour of DR/ADMM when the involved functions are moreover partly smooth. More precisely, when one of the functions and the conjugate of the other are partly smooth relative to their respective manifolds, we show that DR/ADMM identifies these manifolds in finite time. Moreover, when these manifolds are affine or linear, we prove that DR is locally linearly convergent with a rate in terms of the cosine of the Friedrichs angle between the two tangent subspaces. This is illustrated by several concrete examples and supported by numerical experiments.