Given the recent emphasis on Lepidoptera wing color and temperature in macroecology, we briefly describe known drivers of wing color and outline the use of images for understanding color variation across space and time. As a case study, we quantify wing color using museum specimens of the non-migratory Puerto Rican monarch. In contrast to recent findings, we report darker individuals in coastal habitats, underscoring the need to include other selection factors. We detail how international digitization initiatives can resolve this paradox by adopting standards and protocols for high-throughput image analysis.