Porous materials are ubiquitous in natural and engineered systems including ceramics, foams, bone, concrete, filtration membranes, and energy-storage components where microstructural pores provide functionality while simultaneously introducing fracture vulnerability. Because brittle failure in such materials is governed by microscale heterogeneity, accurate prediction of crack initiation and propagation requires computational frameworks that rigorously connect pore-scale morphology to structural-scale fracture response. Despite extensive studies on pore-shape effects on elastic behavior and multiscale fracture modeling, the influence of realistic versus idealized pore morphologies on macroscopic fracture resistance remains insufficiently understood. This work presents a two-scale computational phase-field framework for brittle fracture in porous media with explicitly resolved microstructures. Effective constitutive tensors are first computed via asymptotic homogenization to capture microstructure-induced anisotropy and stiffness degradation. These homogenized properties are then mapped to a macroscale phase-field fracture model based on the variational Griffith formulation, where crack evolution is governed by the competition between elastic strain energy and fracture surface energy. The framework is implemented within an open-source finite element platform to ensure reproducibility and scalability. High-fidelity simulations are performed on systematically generated idealized and realistic pore geometries spanning multiple porosity levels. The results demonstrate that realistic pore architectures produce more compliant effective responses, pronounced anisotropy, and delayed crack initiation compared to simplified microstructural representations. These findings establish quantitative structure-property-fracture relationships across scales and highlight the limitations of idealized pore models in predicting macroscopic brittle failure.