We show that the effective gauge field for photons provides a versatile platform for controlling the flow of light. As an example we consider a photonic resonator lattice where the coupling strength between nearest neighbor resonators are harmonically modulated. By choosing different spatial distributions of the modulation phases, and hence imposing different inhomogeneous effective magnetic field configurations, we numerically demonstrate a wide variety of propagation effects including negative refraction, one-way mirror, and on and off-axis focusing. Since the effective gauge field is imposed dynamically after a structure is constructed, our work points to the importance of the temporal degree of freedom for controlling the spatial flow of light.It was recently recognized that when a photonic structure undergoes dynamic refractive index modulation, the phase of the modulation creates an effective gauge potential and effective magnetic field for photons [1,3]. The effective magnetic field can induce photonic phenomena similar to charged particles under real magnetic field, such as a photonic one-way edge mode [1] and a photonic de Haas-van Alphen effect [4]. In this paper, we further show that the use of inhomogeneous effective gauge fields provide additional degrees of freedom in controlling the flow of light. As examples, we show that one can achieve negative refraction, one-way mirrors, circulators, and focusing, based on the same resonator lattice structure subject to different configurations of inhomogeneous effective gauge fields.Tailoring the propagation of light has been a central goal of nano-photonic research, which is critical for applications in on-chip communications and information processing [5]. Examples of previous studies include the use of waveguide arrays [6,7], photonic crystals [8][9][10][11] and meta-materials [12-14] to achieve various beam propagation effects within these structures. Moreover, by introducing inhomogeneity into these structures [15,16], one can realize photon flow that emulates electron motion under electric field [17][18][19].Complementary to these works, which have largely focused on spatial degrees of freedom, our results here show that temporal degrees of freedom in a dynamic structure can also be quite useful in the control of electromagnetic wave propagations in space. Unlike the spatial (i.e. the structural) degrees of freedom, which are mostly defined by fabrication processes, the modulation phases can be readily changed in the dynamic structure, after the structure is constructed. Moreover, non-reciprocity, or timereversal symmetry breaking, which is difficult to achieve * Current address: Thomas J. Watson, Sr