AI is happening. The future is updating.flux-3-image-klein-pup
FLUX 3 Image Klein Prompt Upsampler is a 9B vision-language model that expands a short image request into the detailed prompt FLUX 3 Image Klein works best with. It takes the request, up to 10 reference images and an optional list of bounding boxes, and returns one prompt. It is a fine-tune of Qwen3.5-9B. FLUX 3 Image Klein is not meant to run without a prompt upsampler in front of it, for text-to-image, editing and layout alike; a short prompt sent to the image model as typed gives generic output. This one is tuned for it, see Training. Any other LLM can do the job with the system prompts in `system_prompts.json`. The inference code in black-forest-labs/flux-3-image-klein loads it by default. With Diffusers, run the Transformers block below and pass the caption to the pipeline as `prompt`. In ComfyUI, the text-to-image templates on flux-3-image-klein-comfy have an `enable_prompt_upsampler` switch. > Full-color outdoor photograph, eye-level medium-wide shot in late afternoon sunlight, showing a man walking his dog along a neighborhood sidewalk. The low sun shines from the upper right, casting long shadows across the pavement and lighting the man's face and clothing with warm side light. Slightly left of center, a white man in his thirties with fair skin, short brown hair, and light stubble walks toward frame-left at an easy pace. He wears a faded olive overshirt over a plain grey T-shirt, dark blue jeans, and worn brown leather shoes. [...]
FLUX 3 Image Klein Prompt Upsampler is a 9B vision-language model that expands a short image request into the detailed prompt FLUX 3 Image Klein works best with. It takes the request, up to 10 reference images and an optional list of bounding boxes, and returns one prompt. It is a fine-tune of Qwen3.5-9B. FLUX 3 Image Klein is not meant to run without a prompt upsampler in front of it, for text-to-image, editing and layout alike; a short prompt sent to the image model as typed gives generic output. This one is tuned for it, see Training. Any other LLM can do the job with the system prompts in `system_prompts.json`. The inference code in black-forest-labs/flux-3-image-klein loads it by default. With Diffusers, run the Transformers block below and pass the caption to the pipeline as `prompt`. In ComfyUI, the text-to-image templates on flux-3-image-klein-comfy have an `enable_prompt_upsampler` switch. > Full-color outdoor photograph, eye-level medium-wide shot in late afternoon sunlight, showing a man walking his dog along a neighborhood sidewalk. The low sun shines from the upper right, casting long shadows across the pavement and lighting the man's face and clothing with warm side light. Slightly left of center, a white man in his thirties with fair skin, short brown hair, and light stubble walks toward frame-left at an easy pace. He wears a faded olive overshirt over a plain grey T-shirt, dark blue jeans, and worn brown leather shoes. [...]