Black Forest Labs releases FLUX 3 Image Klein, a 5.6B open-weights image model

BFL released FLUX 3 Image Klein, a 5.6B open-weights model for generation and editing that it says runs on 8GB GPUs and costs $0.009 per 1K image via API.

Black Forest Labs released FLUX 3 Image Klein on October 15, a 5.6B-parameter open-weights model for text-to-image, image editing and multi-reference generation with up to 10 reference images, according to BFL's announcement. If you make brand or marketing assets, this is an image model you can run, edit with and fine-tune on your own hardware. BFL says the INT8 build runs on GeForce RTX GPUs with as little as 8GB of VRAM through ComfyUI or Diffusers. The hosted API starts at $0.009 per 1K image.

There are two checkpoints: a base model for LoRA fine-tuning and a step-distilled model for fast generation. Bounding boxes can place elements or confine an edit to one region. The ComfyUI model card says the boxes guide placement and scale but do not work as a hard pixel mask.

The quality claims come from BFL itself. Its statement that Klein ranks first among open models comes from internal evaluations, and OrcaRouter found no Klein entry on public leaderboards yet.

Kingy AI's launch-day test ran a 44-image batch on the distilled model for US$0.396. Those outputs passed all four scored checks on 24 of 32 text-to-image prompts, against 31 each for Nano Banana 2.1 and GPT Image 2.5 Flare. Kingy ran the test with prompt expansion turned off, which BFL recommends against.

The reference code says not to use the model without its prompt upsampler, and that changes the hardware picture. OrcaRouter counts roughly 39 GB on disk once the BF16 upsampler is included. Kingy cautions that the 8GB figure doesn't cover every combination of loader, precision and components.

On licensing, BFL says the FLUX Kommunity License allows free commercial use below $5M in annual revenue. Kingy warns this exception is not blanket permission for commercial fine-tuning or redistribution, so read the license before you ship.

Sources