  We present a novel diffractive imaging method that harnesses a low-resolution
real-space image to guide the phase retrieval. A computational algorithm is
developed to utilize such prior knowledge as a real-space constraint in the
iterative phase retrieval procedure. Numerical simulations and proof-of-concept
experiments are carried out, demonstrating our method's capability of
reconstructing high-resolution details that are otherwise inaccessible with
traditional phasing algorithms. With the present method, we formulate a
conceptual design for the coherent imaging experiments at a next-generation
X-ray light source.
