Comparison of the spatially resolved stellar metallicities for 6958 pixel bins in the 25 sample galaxies measured by different prior functions. The true values of Z_★ (x-axis) are compared with those from our fiducial run (y-axis), when a flat prior for Z_★ is used in logarithmic space (left panel) and in linear space (right panel). The dashed orange line shows the one-to-one relation, while contours enclose 20%, 50%, and 80% of the total data. Top-left: Residual distribution, log₁₀(Z_★/Z_{★,  TNG50}). Top-right: Comparison of the true Z_★ values (teal distribution) with those recovered from Prospector (orange distribution). The dotted lines correspond to the prior probability distributions, scaled with an arbitrary factor. The mean offset (μ) and scatter (σ) between the two distributions are indicated in each panel. A flat prior in linear space for Z_★ returns values closer to the ground truth.