"Memory Saver" is an interactive photo booth project created by upcycling used smartphones. Centered around designer Minjae Kang’s philosophy that “design is about saving,” the project focuses on the concept of "saving" in the sense of resource conservation. Through an analysis of the term “saving” in Korean, English, and Chinese, Kang concluded that design should serve to preserve resources and minimize waste. The project also addresses the growing problem of discarded smartphones—more than 5.3 billion worldwide—highlighting the contrast between Korea’s average smartphone replacement cycle (27.9 months) and the global average (43 months). In today’s era of slow growth, the project underscores the increasing importance of functional and practical design. “Memory Saver” integrates retro aesthetics and the self-photo trend, making it easy for anyone to use. Powered by solar energy, the booth features a charming, emotive display that interacts with users while taking their pictures. Suggested applications include city branding campaigns, installations in corporate spaces, and use at weddings or event venues. The project involves design research and prototyping, including UX studies on photo booths, cameras, and displays. Ultimately, it explores the potential of design as a solution that both preserves memories and conserves resources.