The National Gallery of Art developed a systematic approach to evaluate and categorize its extensive digital image collection spanning 20 years of technological evolution. This study addresses the challenge of inconsistent image quality resulting from varying capture technologies and methodologies over time. A four-tier rating system was created based on comprehensive analysis of capture devices, technical specifications, and workflow documentation. The system enables efficient assessment of image suitability for different applications while providing clear guidance for re-digitization decisions. The implementation includes integration with the institution's digital asset management system, offering a practical framework that other cultural heritage institutions can adapt for managing legacy digital collections while maintaining current quality standards.