This work paves the way to realize a processing-in-pixel (PIP) accelerator based on a multilevel HfOx resistive random access memory (RRAM) as a flexible, energy-efficient, and high-performance solution for real-time and smart image processing at edge devices. The proposed design intrinsically implements and supports a coarse-grained convolution operation in low-bit-width neural networks (NNs) leveraging a novel compute-pixel with nonvolatile weight storage at the sensor side. Our evaluations show that such a design can remarkably reduce the power consumption of data conversion and transmission to an off-chip processor maintaining accuracy compared with the recent in-sensor computing designs. Our proposed design, namely an integrated multilevel RRAM (HfOx)-based processing-in-pixel accelerator (MR-PIPA), achieves a frame rate of 1000 and efficiency of ~1.89 TOp/s/W, while it substantially reduces data conversion and transmission energy by ~84% compared to a baseline at the cost of minor accuracy degradation.