InvokeAI Image Generation
Generate images via InvokeAI's REST API. Supports FLUX.2 Klein (default), Z-Image Turbo, FLUX.1, and SDXL.
Quick Start
Simply call the script with your prompt and the output file name:
python scripts/generate.py -p "A dramatic sunset over snow-capped mountains, warm orange light reflecting off a still alpine lake in the foreground. Soft clouds catch the fading light." -o sunset.png
Overriding The Default Model
If the user asks you to use a specific model, first find the model key, then use it in the command:
python scripts/generate.py --list-models | grep -i 'flux'
python scripts/generate.py -p "A tabby cat with bright green eyes sits on a weathered wooden windowsill, soft afternoon light streaming through lace curtains. Cosy, intimate mood." --model MODEL_KEY -o cat.png
Options
| Option | Description |
|---|---|
--prompt, -p | Generation prompt (required) |
--negative, -n | Negative prompt (SDXL only) |
--model, -m | Model key (UUID) or partial name match |
--width, -W / --height, -H | Dimensions |
--steps, -s | Denoising steps |
--cfg, -c | CFG scale |
--guidance, -g | Guidance strength (FLUX.1 only) |
--scheduler | Sampling scheduler |
--seed | Random seed |
--output, -o | Output path (default: invokeai-{seed}.png) |
--list-models | List installed models |
--json | JSON output |
Model Defaults
Note: FLUX.2 Klein is the latest model which is used by default.
| Model | Steps | Guidance | CFG | Scheduler |
|---|---|---|---|---|
| FLUX.2 Klein | 4 | 3.5 | 1.0 | euler |
| Z-Image Turbo | 9 | - | 1.0 | euler |
| FLUX.1 dev | 28 | 3.5 | 1.0 | euler |
| FLUX.1 Krea dev | 28 | 4.5 | 1.0 | euler |
| FLUX.1 Kontext dev | 28 | 2.5 | 1.0 | euler |
| FLUX.1 schnell | 4 | 0.0 | 1.0 | euler |
| SDXL | 25 | - | 6.0 | dpmpp_2m_k |
| SDXL Turbo | 8 | - | 1.0 | dpmpp_sde |
All models default to 1024x1024. FLUX requires dimensions divisible by 16, SDXL by 8.
FLUX.1 Variant Notes
- FLUX.1 dev: Standard text-to-image model, balanced quality/speed
- FLUX.1 Krea dev: Fine-tuned for aesthetic photography, use higher guidance (4.5)
- FLUX.1 Kontext dev: Image editing model, use lower guidance (2.5)
- FLUX.1 schnell: Distilled fast model, 4 steps, no guidance needed
Model Selection
Auto-priority: Klein > Z-Image > FLUX > SDXL
Detection by name/base:
- flux2_klein: "klein" in name or "flux2" in base
- flux_krea: "krea" in name (FLUX.1 base)
- flux_kontext: "kontext" in name (FLUX.1 base)
- flux_schnell: "schnell" in name (FLUX.1 base)
- flux: "flux" in base (standard dev)
- zimage: "z-image" in base or "z-image/zimage" in name
- sdxl: "sdxl" in base (turbo/lightning variants auto-detect)
Prompting (general information, but especially useful for FLUX.2 Klein)
Write prose, not keywords. Structure: Subject -> Setting -> Details -> Lighting -> Atmosphere
A weathered fisherman in his late sixties stands at the bow of a wooden boat,
wearing a salt-stained wool sweater. Golden hour sunlight filters through
morning mist, creating quiet determination and solitude.
Key techniques:
- Front-load critical elements (word order matters)
- Specify lighting: source, quality, direction, temperature
- Include sensory texture: materials, reflections, atmosphere
Good: "A woman with short blonde hair poses against a light neutral background wearing colourful earrings, resting her chin on her hand."
Bad: "woman, blonde, short hair, neutral background, earrings"
Append style tags: Style: Country chic. Mood: Serene, romantic.
Troubleshooting
| Issue | Solution |
|---|---|
| Connection refused | Check InvokeAI is running |
| Model not found | Use --list-models for valid keys |
| Dimensions error | FLUX: multiples of 16, SDXL: 8 |
| Black images (macOS) | Set precision: bfloat16 in invokeai.yaml |
If the script fails to find the URL or authentication token, you can set or ask the user to set environment variables:
export INVOKEAI_API_URL='http://localhost:9090'
export INVOKEAI_AUTH_TOKEN='your-token' # Optional
Resources
scripts/generate.py- Main generation script