Tech Feb 14, 2026 5 min Why are image-generation VAEs so heavy? Comparing the Qwen-Image and HunyuanImage architectures An explanation of why Qwen-Image-Edit's VAE is so heavy, how HunyuanImage 2.1 chose a 32x high-compression VAE instead, and how Kohya's memory-optimization work fits in. AI Image Generation VAE Qwen HunyuanImage Memory Optimization