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All FLUX.1 variants support resolutions between 0.1 and 2.0 megapixels across a wide range of aspect ratios
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FLUX 1.1 Pro Ultra delivers up to 2K output (up to 2048×2048, 4 megapixels). 4x the resolution of standard FLUX 1.1 [pro]
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Supported ratios include 1:1, 16:9, 9:16, 3:2, 2:3, 4:5, 5:4, 4:3, and custom dimensions
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FLUX.1 [schnell] generates in 1 to 4 inference steps with sub-second response times
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FLUX 1.1 [pro] is six times faster than its predecessor FLUX.1 [pro] while improving image quality and prompt adherence
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FLUX 1.1 Pro Ultra generates in approximately 10 seconds per image. Suited to print and editorial workflows, not real-time use
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Text-to-image generation across all variants
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Image conditioning on FLUX 1.1 Pro Ultra via `image_url` and `image_prompt_strength` (0–1 range) for style transfer and composition control
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Mask-based inpainting and object removal via FLUX 1.1 Pro Fill
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Style and composition variation from a reference image via FLUX 1.1 Pro Redux
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WebP, JPEG, and PNG outputs supported
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FLUX.1 [schnell] includes a built-in NSFW safety checker, enabled by default
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FLUX 1.1 [pro] exposes a `safety_tolerance` parameter (range 1–6, default 2) for configurable content filtering
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FLUX.1 [schnell] is open-weight under Apache 2.0, with weights on Hugging Face and day-1 ComfyUI integration
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FLUX.1 [dev] is open-weight but restricted to non-commercial use. Commercial licensing requires contacting Black Forest Labs directly
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FLUX 1.1 [pro], FLUX 1.1 Pro Ultra, FLUX 1.1 Pro Fill, FLUX 1.1 Pro Redux, FLUX.2 [pro], and FLUX.2 [klein] are available for commercial use via the licensed API