This paper delves into the strategic design and optimization of silver (Ag) nanostructured arrays within plasmonic metamaterials, targeting the enhancement of imaging sensitivity. Leveraging Finite-Difference Time-Domain (FDTD) simulations, our research rigorously compares various Ag nanostructured geometries, including nanospheres, nanocones, nanodisks, and nanocubes. The aim is to pinpoint configurations that significantly enhance electric field localization on the surfaces of nanostructures, a pivotal factor. The nanocube array exhibits superior field enhancement, particularly in narrow nanogaps, suggesting its suitability for high-sensitivity applications. Further exploration into nanocube arrays reveals the crucial role of nanogap size and spacer layer thickness in tuning the optical properties through the manipulation of Fabry–Pérot and mirror image modes in metal–insulator–metal (MIM) structures. By presenting a thorough analysis of these nanostructured arrays, the study not only contributes to our understanding of the fundamental principles governing plasmonic metamaterials but also provides a solid foundation for future innovation in highly sensitive imaging applications. It underscores the importance of nanostructure design and optimization in achieving significant improvements in the performance of plasmonic devices, marking a pivotal step forward in the field of nanophotonics and its application to sensitive imaging technologies.