> ## Documentation Index > Fetch the complete documentation index at: https://docs.yelinai.com/llms.txt > Use this file to discover all available pages before exploring further. # Flux Image Generation API > Generate high-quality images using Flux Kontext Pro/Max models, supports multiple aspect ratios with better value than official pricing ## Prerequisites 1 Get API Key Log in to [YeLIn AI console](https://api.yelinai.com) to obtain your API key 2 Configure Billing Mode Edit token settings and choose one of the following billing modes (same price for both): * **Volume Priority** (Recommended): Uses balance billing first, automatically switches when balance is insufficient. Suitable for most users * **Pay-per-call**: Direct deduction for each call. Suitable for strict budget control scenarios Both modes have **exactly the same price**, Flux Kontext Pro $0.035/image, Flux Kontext Max $0.07/image, only the billing method differs. 请在 **Console** 查看对应界面截图。 If billing mode is not configured, API calls will fail. You must complete this configuration first! ## Flux Image Generation API Flux is an industry-leading image generation model. Through LaoZhang API’s OpenAI-compatible interface, you can easily call Flux Kontext Pro and Max models to generate high-quality images. We offer better pricing than official rates, combined with exchange rate advantages and recharge bonuses to save you more costs. **🎯 High-Quality Generation**\ Flux models are renowned for exceptional image quality and detail, supporting flexible aspect ratios from 3:7 to 7:3. ## 🌟 Core Features * **📐 Flexible Ratios**: Supports continuous aspect ratio range from 3:7 to 7:3 * **🎨 High-Quality Output**: 1 megapixel images with rich details and artistic expression * **💰 Price Advantage**: Better rates than official pricing, cost savings * **🔧 OpenAI Compatible**: Uses standard Images API format, easy integration * **⏱️ URL Validity**: Generated result URLs valid for 10 minutes, download promptly * **🔄 Reproducibility**: Supports seed parameter for consistent results ## 📋 Model Comparison | Model | Model ID | LaoZhang API Price | Official Price | Savings | Features | | -------------------- | ------------------ | ------------------ | -------------- | ------- | -------------------------------------- | | **Flux Kontext Pro** | `flux-kontext-pro` | \$0.035/image | \$0.040/image | 12.5% | Cost-effective, suitable for batch use | | **Flux Kontext Max** | `flux-kontext-max` | \$0.07/image | \$0.08/image | 12.5% | Highest quality, professional use | 💡 **Price Advantage**: Call Flux models through LaoZhang API platform, combined with exchange rate advantage (1:7) and recharge bonus policy (top up \$100, get +10% bonus), save over 25% compared to official pricing! ## 📐 Supported Aspect Ratios Flux models support continuous aspect ratio range from **3:7 to 7:3**, maintaining approximately 1 megapixel total. Here are some common ratio examples: | Ratio | Type | Approximate Size | Use Case | | ------ | ------------------- | ---------------- | ------------------------------------ | | `1:1` | Square | 1024×1024 | General use, social media avatars | | `2:3` | Vertical | \~832×1248 | Phone wallpapers, portrait photos | | `3:2` | Horizontal | \~1248×832 | Desktop wallpapers, landscape photos | | `4:3` | Standard Horizontal | \~1182×886 | Traditional displays, presentations | | `16:9` | Widescreen | \~1408×792 | Modern displays, video thumbnails | | `9:16` | Vertical Screen | \~792×1408 | Mobile videos, vertical posters | | `21:9` | Ultra-wide | \~1680×720 | Movie posters, ultra-wide displays | | `3:7` | Narrowest Vertical | \~662×1544 | Bookmarks, vertical long images | | `7:3` | Widest Horizontal | \~1544×662 | Website banners, panoramic images | **📏 Custom Ratios**: Besides the examples above, you can use any ratio within the 3:7 to 7:3 range, such as `5:4`, `4:5`, `16:10`, etc. The system automatically adjusts size to maintain approximately 1 megapixel total area. ## 🚀 Quick Start ### Basic Example ``` from openai import OpenAI # Initialize client client = OpenAI( api_key="YOUR_API_KEY", base_url="https://api.yelinai.com/v1" ) # Generate image (full parameters version) def generate_flux_image(prompt, aspect_ratio="1:1", model="flux-kontext-pro", seed=None, safety_tolerance=2, output_format="jpeg", prompt_upsampling=False): """ Generate Flux image Parameters: - prompt: Image description text - aspect_ratio: Aspect ratio (3:7 to 7:3) - model: Model selection - seed: Random seed for reproducibility - safety_tolerance: Content safety level (0-6) - output_format: Output format "jpeg" or "png" - prompt_upsampling: Whether to enhance prompt """ try: # Build extra_body parameters extra_params = { "aspect_ratio": aspect_ratio, "safety_tolerance": safety_tolerance, "output_format": output_format, "prompt_upsampling": prompt_upsampling } # Optional parameters if seed is not None: extra_params["seed"] = seed response = client.images.generate( model=model, prompt=prompt, extra_body=extra_params ) # Get image URL (note: expires after 10 minutes) image_url = response.data[0].url return image_url except Exception as e: print(f"Generation failed: {e}") return None # Usage example image_url = generate_flux_image( prompt="A futuristic city with flying cars and neon lights", aspect_ratio="16:9", model="flux-kontext-pro", seed=42, # Fixed seed for reproducibility safety_tolerance=2, # Default safety level output_format="png", # High-quality PNG format prompt_upsampling=True # Enhance prompt effect ) if image_url: print(f"Generated image: {image_url}") print("⚠️ Note: URL will expire after 10 minutes, download promptly!") ``` ## 📝 Parameter Details ### Parameters Passed via extra\_body | Parameter | Type | Range/Options | Description | Default | | ------------------- | ------- | ------------- | --------------------------------------------------- | ------- | | `aspect_ratio` | string | 3:7 to 7:3 | Output image aspect ratio | ”1:1” | | `seed` | integer | Any integer | Random seed for reproducibility | Random | | `safety_tolerance` | integer | 0-6 | Content safety control, 0=strictest, 6=most lenient | 2 | | `output_format` | string | ”jpeg”, “png” | Output image format | ”jpeg” | | `prompt_upsampling` | boolean | true/false | Auto-enhance prompt | false | **💡 Prompt Enhancement**: Enabling `prompt_upsampling` allows AI to automatically optimize and expand your prompt, but may change original intent. Recommended to test first. ## 💡 Best Practices ### 1. URL Management and Download Strategy Since Flux generated image URLs are **only valid for 10 minutes**, proper download strategy is crucial: ``` import time import requests class FluxImageManager: """Flux image generation and download manager""" def __init__(self, api_key, base_url="https://api.yelinai.com/v1"): self.client = OpenAI(api_key=api_key, base_url=base_url) def generate_and_save(self, prompt, **kwargs): """Generate image and save immediately""" start_time = time.time() # Generate image image_url = generate_flux_image(prompt, **kwargs) if not image_url: return None # Download immediately (avoid timeout) elapsed = time.time() - start_time if elapsed > 540: # Over 9 minutes print("⚠️ Warning: Approaching URL expiration time!") # Download and save filename = f"flux_{int(time.time())}.png" try: response = requests.get(image_url, timeout=30) response.raise_for_status() with open(filename, 'wb') as f: f.write(response.content) print(f"✅ Saved: {filename} (elapsed: {elapsed:.1f}s)") return filename except Exception as e: print(f"❌ Download failed: {e}") return None ``` ### 2. Model Selection Guide **Flux Kontext Pro**: * ✅ Daily design needs * ✅ Batch content generation * ✅ Cost-sensitive projects * ✅ Rapid prototyping **Flux Kontext Max**: * ✅ Professional design works * ✅ Commercial use images * ✅ High-quality requirements * ✅ Print output needs ### 3. Prompt Optimization Based on official documentation recommendations, detailed and descriptive prompts yield better results: ``` # ❌ Too simple prompt = "cat" # ✅ Detailed description prompt = """ A majestic orange tabby cat sitting by a window, golden hour lighting, soft focus background, professional pet photography style, warm and cozy atmosphere """ # ✅ Use prompt_upsampling to enhance simple prompts enhanced_result = generate_flux_image( prompt="cat by window", prompt_upsampling=True # AI automatically expands and optimizes prompt ) # ✅ Artistic style prompts artistic_prompt = """ A surreal landscape painting in the style of Salvador Dali, melting clocks draped over twisted trees, vibrant sunset colors bleeding into a starry night sky, hyper-detailed, dreamlike atmosphere """ ``` ## ⚠️ Important Notes 1. **URL Validity**: * Generated image URLs are **only valid for 10 minutes** * Must download before expiration * Recommended to download immediately after generation 2. **Parameter Passing**: * All Flux-specific parameters must be passed via `extra_body` * Cannot use Flux proprietary parameters directly in top-level parameters 3. **Aspect Ratio Range**: * Supports continuous range from 3:7 to 7:3 * Not limited to fixed ratios, can use any ratio within range * System auto-adjusts size to maintain \~1 megapixel 4. **Content Safety**: * `safety_tolerance` parameter controls moderation strictness (0-6) * 0 = strictest, 6 = most lenient * Default value 2 suitable for most scenarios 5. **Output Format**: * Default JPEG format, smaller files * PNG format higher quality but larger files * Choose appropriate format based on use case 6. **Prompt Processing**: * `prompt_upsampling` auto-optimizes prompts * May change original intent, recommended to test first * Significant effect on simple prompts ## 🔍 FAQ ### Q: Why do image URLs expire? A: This is Flux official’s security design. All generated image URLs automatically expire after 10 minutes. Please download and save promptly. ### Q: How is Flux different from other models? A: Flux models focus on high-quality image generation, supporting flexible aspect ratios (3:7 to 7:3), particularly suitable for professional designs requiring specific dimensions. ### Q: How to choose between Pro and Max versions? A: * **Pro**: Cost-effective, \$0.035/image, suitable for daily use and batch generation * **Max**: Highest quality, \$0.07/image, suitable for commercial works and professional needs ### Q: Can I use any aspect ratio? A: You can use any ratio within the 3:7 to 7:3 range, such as `5:4`, `16:10`, `21:9`, etc. The system auto-adjusts to maintain \~1 megapixel. ### Q: How to set safety\_tolerance? A: * 0-1: Corporate/commercial environment, strictest * 2-3: General creation, balanced mode (recommended) * 4-6: Artistic creation, more lenient ### Q: What does prompt\_upsampling do? A: When enabled, AI automatically expands and optimizes your prompt, especially suitable for brief prompts. But may change original meaning, recommended to test first. ### Q: How to ensure reproducible results? A: Use the same `seed` value and identical other parameters to generate consistent results. This is helpful for iterative design. ### Q: How to avoid URL expiration in batch generation? A: 1. Download immediately after generation 2. Use concurrency control to avoid excessive processing time 3. Consider using async processing for efficiency ## 🎯 Multi-Image Processing Solution Flux API natively only supports single image input, but through our batch processing scripts, you can achieve **dual-image composition processing**. ### Use Cases * **Pattern Transfer**: Transfer design patterns onto clothing models * **Style Fusion**: Combine characteristic elements from two images * **Comparison Display**: Show original and target effect simultaneously ### Technical Approach Image Merging Strategy 1. **Auto Download**: Fetch two input images from URLs 2. **Smart Merge**: Use Python PIL to stitch images side by side 3. **API Call**: Use merged image as single input 4. **Result Processing**: AI performs intelligent processing based on merged image Batch Processing Capability * Supports automated processing of multiple image pairs * Unified prompt control for processing effects * Automatic result download and file management * Complete error handling and logging ### Quick Start Shell Script Python Implementation ``` # Download batch processing script wget https://raw.githubusercontent.com/laozhang-api/ai-api-code-samples/main/flux-Image-API/flux-simple-batch.sh chmod +x flux-simple-batch.sh # Modify configuration # 1. Set your API_KEY # 2. Configure image pair array # 3. Customize processing prompt # Run batch processing ./flux-simple-batch.sh ``` **Dependency Requirements**: Script requires `jq`, `Python3 + PIL`, and optionally `ImageMagick`. See script help for detailed installation instructions. ## 🔗 Related Resources * [Complete Example Code](https://github.com/laozhang-api/ai-api-code-samples/tree/main/flux-Image-API) * [Multi-Image Processing Script](https://github.com/laozhang-api/ai-api-code-samples/blob/main/flux-Image-API/flux-simple-batch.sh) * [Flux Image Edit API](/api-capabilities/flux-image-edit) - Edit existing images * [Pricing Calculator](https://api.yelinai.com/account/pricing) - Real-time price query * \[Online Demo]\([https://imagen.YeLIn](https://imagen.YeLIn) AI) - Test Flux effects 🎨 **Pro Tip**: Combining different aspect ratios and model versions can meet various needs from social media to professional design!