The AI-generated inspirational images provided a new pathway for design learners to obtain inspiration, but previous research had overlooked the impact of the emotional valence and arousal of AI-generated images on design creativity. This study investigated the effects of emotional valence and arousal of AI-generated images on design creativity through two experiments. Experiment 1 examined the impact of emotional valence (positive, neutral, negative) of AI-generated images on design creativity, while Experiment 2 further analyzed the impact of arousal levels (high, low) of AI-generated images and design problem types (conceptual design problems, knowledge design problems) on design creativity under positive emotional conditions. The results showed that AI-generated images with positive emotional valence facilitated divergent thinking and enhanced the flexibility and originality of creative ideas. In knowledge design problems, AI-generated images with positive emotional valence and high arousal levels enhanced the originality of creative ideas. However, in conceptual design problems, the arousal levels of AI-generated images with positive emotional valence had no significant impact on design creativity. These findings provided insights into how design learners could utilize AI assistance in design.