Generate Image with fal.ai

Generate AI images using fal.ai models like FLUX, Stable Diffusion, and more.

What This Command Does

Guides you through generating images with fal.ai, selecting the optimal model and parameters for your use case.

Steps

1. Gather Requirements

   • Prompt description
   • Image size and aspect ratio
   • Quality vs speed preference
   • Output format requirements

2. Select Model

   • FLUX.1 [dev] - High quality, open-source
   • FLUX.2 [pro] - Best quality, production
   • FLUX Schnell - Fast generation
   • Fast SDXL - Speed optimized
   • Recraft V3 - Design assets

3. Configure Parameters

   • num_inference_steps (quality)
   • guidance_scale (prompt adherence)
   • seed (reproducibility)
   • safety checker settings

4. Generate Code

   • JavaScript/TypeScript or Python
   • Error handling
   • Progress feedback

Quick Reference

Model Selection Guide

Need	Recommended Model	Why
Best quality	fal-ai/flux-2-pro	Latest FLUX, highest fidelity
Fast iteration	fal-ai/flux/schnell	4-step generation
Open source	fal-ai/flux/dev	12B parameter model
Budget friendly	fal-ai/fast-sdxl	Lower cost per image
Custom styles	fal-ai/flux-lora	Fine-tuned models
Design work	fal-ai/recraft-v3	Vector-style outputs

Image Sizes

Preset	Dimensions	Use Case
square	512x512	Thumbnails, icons
square_hd	1024x1024	Social media
portrait_4_3	768x1024	Portraits
portrait_16_9	576x1024	Mobile wallpapers
landscape_4_3	1024x768	Presentations
landscape_16_9	1024x576	Widescreen

JavaScript/TypeScript Example

import { fal } from "@fal-ai/client";

fal.config({ credentials: process.env.FAL_KEY });

async function generateImage(prompt: string) {
  const result = await fal.subscribe("fal-ai/flux/dev", {
    input: {
      prompt,
      image_size: "landscape_16_9",
      num_inference_steps: 28,
      guidance_scale: 3.5,
      num_images: 1,
      enable_safety_checker: true,
      output_format: "jpeg"
    },
    logs: true,
    onQueueUpdate: (update) => {
      if (update.status === "IN_PROGRESS") {
        console.log("Generating...", update.logs);
      }
    }
  });

  return result.images[0].url;
}

Python Example

import fal_client

def generate_image(prompt: str) -> str:
    result = fal_client.subscribe(
        "fal-ai/flux/dev",
        arguments={
            "prompt": prompt,
            "image_size": "landscape_16_9",
            "num_inference_steps": 28,
            "guidance_scale": 3.5,
            "num_images": 1,
            "enable_safety_checker": True,
            "output_format": "jpeg"
        },
        with_logs=True,
        on_queue_update=lambda update: print(f"Status: {update}")
    )
    return result["images"][0]["url"]

Advanced Features

Image-to-Image:

const result = await fal.subscribe("fal-ai/flux/dev/image-to-image", {
  input: {
    image_url: "https://example.com/input.jpg",
    prompt: "Transform into oil painting style",
    strength: 0.75
  }
});

Inpainting:

const result = await fal.subscribe("fal-ai/flux/dev/inpainting", {
  input: {
    image_url: "https://example.com/photo.jpg",
    mask_url: "https://example.com/mask.png",
    prompt: "A golden retriever"
  }
});

ControlNet:

const result = await fal.subscribe("fal-ai/flux/dev/controlnet", {
  input: {
    prompt: "Modern architecture",
    control_image_url: "https://example.com/edges.png",
    controlnet_conditioning_scale: 0.8
  }
});

Parameter Tuning

num_inference_steps

• Low (4-10): Fast, lower quality - use with Schnell
• Medium (20-30): Balanced - recommended default
• High (40-50): Maximum quality, slower

guidance_scale

• Low (1-3): More creative, less prompt adherence
• Medium (3.5-7): Balanced - recommended
• High (8-15): Strict prompt following

Seed

• Use same seed for reproducible results
• Combine with identical parameters for variations

Error Handling

import { fal, ValidationError, ApiError } from "@fal-ai/client";

try {
  const result = await fal.subscribe("fal-ai/flux/dev", {
    input: { prompt: "Your prompt" }
  });
} catch (error) {
  if (error instanceof ValidationError) {
    console.error("Invalid parameters:", error.body);
  } else if (error instanceof ApiError) {
    if (error.status === 429) {
      console.error("Rate limited, retry later");
    } else {
      console.error("API error:", error.message);
    }
  }
}

Cost Optimization

1. Start with Schnell for iteration, switch to dev/pro for final
2. Use appropriate sizes - don't generate larger than needed
3. Batch similar requests when possible
4. Cache results by seed for reproducible outputs