FLUX 3 Klein is Now in ComfyUI: Open Weights & Native 4K

FLUX 3 Image Klein is Black Forest Labs’ compact, open-weights image model, and it now runs natively in ComfyUI. At 5.6B parameters, it brings the control features of the full FLUX 3 Image model to a single consumer GPU. In this video: → Base vs. Distilled: which checkpoint fits fine-tuning and which fits fast iteration → Native 4K generation → Using bounding boxes to control composition and layout → Multi-reference generation and editing with consistent characters → Text rendering and editing inside images → Reference-based style transfer → The prompt upsampler Performance: with INT8 ConvRot