Statistics of PSD analysis (>70 traces) of the studied films is provided in Figure . The average characteristic time τ for MAPI-POR is approximately twice larger than that of the other two samples. The average β slightly decreases from MAPI-LG to MAPI-POR to MAPI-SG. However, for all samples, the average β remains close to 2 suggesting that PL fluctuations are primarily controlled by a specific type of metastable NR center with a characteristic switching time ranging 5 from 0.2-1.5 s. Since the traces resembles the convoluted signal of several two-level systems, we conclude that several of these traps are at work in each functional structure or grain. A detailed analysis aided by simulations is provided in Supporting Notes VII-VIII. The values obtained with the fitting can be mapped back to their emanating position in the sample as illustrated on MAPI-LG in Supporting Figure . In general, photovoltaic device properties are inferred from the behavior of the active material (here, metal-halide perovskite) measured individually in its bare state or on a glass substrate. Consequently, the results obtained may not accurately represent the actual device functionality. A difficulty in studying the active layer in operando arises from the layered architecture, which consists of contact layers and electrodes, rendering it inaccessible to most high-resolution microscopy methods. Therefore, imaging local structures, especially with contrasts related to the optoelectronic response of an active material in a device, is crucial yet rare. Moreover, it is important to study how these microstructures evolve under operation and how they impact device performance, a key determinant of device efficiency. CLIM can fill this gap and is applicable to any device possessing local photo or electroluminescence fluctuations. Figure illustrates measurements on an efficient MAPI-based solar cell (power conversion efficiency of 18.5% under 1 Sun, see Supporting Note X) under 0.15 W/cm^2 illumination, operating at 0.3 V and at 0.7 V. In both cases, the photocurrent is about the same according to the J-V curve. Since PL fluctuates very substantially at low voltage conditions, CLIM reveals functional images. The key observations include: (i) the PL of the MAPI active layer is more heterogeneous and consists of larger clusters of several synchronously fluctuating grains compared to its glass substrate counterpart (LG, Figure ). (ii) PL intensity fluctuations of the clusters is much stronger than in the bare film. (iii) PL fluctuations depend on the J-V condition of the device. While at low voltage, the average PL intensity is low and fluctuating, it becomes high and nonfluctuating at higher voltages (V>0.7 V). It is evident from the first two observations that the mechanism of PL fluctuation in devices is not the same as in films, the latter being well described by a "super-trap" model (see SI Note X for details). This notable difference arises from the presence of transport layers, electrodes, or voltage. Since the main PL quenching mechanism in a solar cell is charge extraction by the contacts, the fluctuation of this process is likely to be the reason behind the PL fluctuations, indicating a dynamic interplay at the interface between the perovskite layer and the charge transport layers. For the PL of a multi-grain cluster to fluctuate, the contact "quality" for all these grains should change synchronously, meaning there must be some communication over several micrometers between the grains comprising the cluster. This can occur via lateral charge carrier transport between grains. In this case, a local opening of an extra charge extraction channel at one grain influences the charge extraction for all grains in the cluster, causing them to fluctuate synchronously. Alternatively, a simultaneous change in the properties of the interface between the cluster and the electrode, such as local charging/discharging can also be responsible for synchronous fluctuations.