Black Forest Labs opens FLUX 3 Image Klein
FLUX 3 Image Klein is a 5.6B-parameter open-weights model for image generation, editing and multi-reference work with up to 10 images. It supports native 4K and bounding boxes to control where things go.
What it does
FLUX 3 Image Klein is a 5.6B-parameter open-weights model for text-to-image, image editing and multi-reference generation with up to 10 images. It supports native 4K and bounding boxes that set where things go or limit an edit to one area.
The release includes a base model for fine-tuning, a fast distilled model, and FP8, INT8 and NVFP4 builds.
Results and limits
In BFL's internal evaluations it ranks first among the open models compared in text-to-image, multi-reference and editing, and beats FLUX.2 [klein] 9B by 91 Elo on text-to-image. NVIDIA measured about 4 seconds per 1MP image on an RTX 5090 and under 9 seconds on an RTX 4070 (distilled model, INT8, ComfyUI).
Worth knowing
The INT8 build runs on GeForce RTX GPUs with as little as 8 GB VRAM via ComfyUI or Diffusers. It's released under the FLUX Kommunity License, not a fully permissive license, and is also available in the BFL API. On 17 October BFL updated its ComfyUI workflows (update to ComfyUI v0.41.3) and said results are best with its prompt upsampling and 2K resolutions.
Try it yourself
In ComfyUI, load the distilled INT8 build and prompt: "[Concept art description], [style], 16:9." Then draw a bounding box around [area] and edit only that: "[change]".