We observe experimentally the transfer of angular spectrum and image formation in the process of stimulated parametric down-conversion. Images and interference patterns can be transferred from either the pump or the auxiliary laser beams to the stimulated down-converted one. The stimulated field propagates as the complex conjugate of the auxiliary laser. The phase conjugation is observed through intensity pattern measurements. DOI: 10.1103/PhysRevLett.87.133602 PACS numbers: 42.50.Ar, 42.25.Kb The cavity-free stimulated down-conversion is a threewave mixing (TWM) process. TWM has been viewed as a nonlinear optical process, with promising applications for correcting wave front distortions. However, when this process was described by a quantum theory [1], new possibilities were opened. The importance of the quantum approach is closely related to the great success of the spontaneous parametric down-conversion in quantum optics [2] and the connection between the stimulated and the spontaneous processes. The quantum properties of the stimulated down-conversion light has not yet been the subject of intense investigation. It was experimentally observed and studied by Mandel and co-workers [3]. Special attention was given to its coherence properties, presenting characteristics of thermal and coherent states [1,3,4], but its individual quantum state was never put forward.In this Letter, we study experimentally the transfer of angular spectrum and image formation in the stimulated down-conversion, as predicted in Ref. [5]. It was also predicted that the stimulated field propagates as the complex conjugate of one of the input fields. The understanding of the angular spectrum transfer has allowed the observation of the phase conjugation by direct intensity measurements. Our results have a classical counterpart (except for the spontaneous emission part) in the framework of the TWM, but they support the quantum theory of Ref. [5]. The relation between the angular spectrum of the pump, auxiliary (signal), and stimulated (idler) beams has not been demonstrated thus far, to the best of our knowledge. These relations are important because they will help us to separate the spontaneous from the stimulated emission contributions in the total idler field which will help us understand phase conjugation at the quantum level [6].