Enabling prompt expansion adds 5-10 seconds to Wan 2.5's typical 15-30 second generation time because it uses a language model to interpret and enrich your input before image synthesis begins. This feature analyzes your prompt, adds compositional details, refines lighting descriptions, and improves stylistic coherence—essentially acting as a creative assistant. For users new to prompt engineering or working with brief descriptions, expansion dramatically improves output quality. However, experienced users with detailed, well-structured prompts may prefer disabling it to maintain exact creative control and reduce processing time. Test both approaches: enable expansion for exploratory work and disable it when you need precise adherence to specific instructions. Compare results with
Kling Image v3 which offers different prompt interpretation styles.