FLUX.2 Klein Generates Images in Under a Second and Unlocks Midjourney‑Style Prompts

Model variants and licensing

FLUX.2 [klein] released by Black Forest Labs. Two checkpoints: Klein 4B (Apache 2.0, commercial use, fine‑tuning) and Klein 9B (open weights for research/prototyping). Both run on consumer GPUs with ≥13 GB VRAM.

Speed and inference

Official benchmark: 1024×1024 image generation or editing in ≤0.5 s on RTX 4090/4070. Latency reduced 5–10× versus typical 20–30‑step diffusion pipelines thanks to a 4‑step inference technique.

Quantized variants:

FP8 mode : 1.6× faster, 40 % VRAM saved.

NVFP4 mode : 2.7× faster, 55 % VRAM saved.

Quality comparison

According to BFL’s official comparison chart, FLUX.2 [klein] matches Stable Diffusion 3 and Midjourney V6 in photo‑realism and style consistency, exceeds SDXL in multi‑reference composition control, and shows higher diversity than distilled variants.

Download

https://bfl.ai/models/flux-2-klein

Community test cases

@gosrum used Japanese prompts for anime‑style editing, achieving flat colour blocks and line‑art conversion.

@victormustar recreated classic “The Legend of Zelda” scenes, converting retro pixel art to high‑definition.

@xr_ymchn applied image‑to‑image in ComfyUI to change a photo into a vivid CG style.

@SD_Tutorial compared the base 50‑step model with the distilled 4‑step version; the distilled model retained acceptable quality while offering large efficiency gains.

Midjourney‑style style reference prompts (SREF)

Four prompts with identifiers:

A dark, atmospheric illustration style with heavy fog, muted tones, and lonely urban spaces.
💫 --sref 1558701018

This SREF creates a minimal, misty landscape.
💫 --sref 1364495918

Whimsical Storybook Illustration
📚 --sref 1891877225

Soft, detailed watercolor and ink style reminiscent of classic children’s books. Gentle pastel colors, charming characters, intricate linework.

Surreal Graphic Illustration
👁️ --sref 4214468475

Intricate line art with flat, stylized colors. Surreal imagery blended with graphic‑novel feel, using patterns and a pink‑green palette.