This study aims to explore the potential of integrating generative artificial intelligence (GAI) into writing instruction to enhance students’ writing abilities. By using AI-generated visual images as writing prompts, the approach stimulates learners’ writing inspiration. The study adopts a quasi-experimental design to evaluate the impact of generative AI tools on writing performance and cognitive abilities, with data collected through pre- and post-tests as well as classroom observations. The results show that AI-generated images significantly improve students’ narrative structure, creative idea generation, and writing fluency. These findings highlight the potential of AI-generated visuals as an innovative instructional tool that offers personalized and context-rich learning experiences with practical applications in education.