flux-3-image-klein-pup: novedades, hardware necesario, cómo usarlo gratis

FLUX 3 Image Klein Prompt Upsampler turns a short request into a full-length prompt for the FLUX 3 image model. It even accepts up to ten reference images and optional bounding boxes.

FLUX 3 Image Klein Prompt Upsampler is a 9.4 billion-parameter vision-language model. It takes a brief description, a set of reference pictures, and optionally a JSON list of bounding boxes, then returns a single caption that contains scene, lighting, camera angle, subject details and exact box references. The caption is ready to feed straight into the FLUX 3 Image Klein generator, whether you are doing text-to-image, image-to-image editing, or layout-guided generation.

According to Black-forest, the upsampler is a full fine-tune of Qwen3.5-9B with the vision tower frozen. Training happened in two stages: first on pairs of short requests and their expanded prompts, then on preference data where the model’s own prompts were ranked after rendering with FLUX 3 Image Klein. The result is a model that knows exactly which details the image generator needs, without extra system prompting.

The biggest strength is that the output prompt already contains medium, style, lighting, camera angle and per-subject attributes, so the image model can produce high-quality results without generic defaults. Bounding-box coordinates are kept verbatim, letting you control placement precisely. Limits include English-only prompts, and reference images are resized to at most one megapixel, which can cause loss of tiny details. The model does not refuse requests, so external safety checks are recommended.

If you already run FLUX 3 Image Klein locally, this upsampler is a natural companion. It fits on a RTX 4060 in 4-bit mode, using about 8 GB of memory, and runs at roughly 45 tokens per second on a RTX 3060 with 12 GB VRAM. Faster cards reach up to 190 tokens per second.

¿Qué necesitas para ejecutarlo en casa? A 4 bits ocupa unos 8 gigabytes de memoria. El equipo doméstico más pequeño que lo aloja por completo es un RTX 4060. Con un RTX 3060 12 GB y 32 gigabytes de RAM escribe unos 45 tokens por segundo. Con un RTX 4090 y 64 gigabytes de RAM escribe unos 116 tokens por segundo.

Aún no hay API gratuita para ello. Los pesos son abiertos: puedes descargarlos de Hugging Face bajo la licencia Apache 2.0. Arena aún no lo ha clasificado: añadiremos la puntuación en cuanto lleguen los votos.

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