Agnes Image 2.1 Flash - Agnes-Ai Docs

Agnes Image 2.1 Flash is an upgraded image generation model from Sapiens AI. It supports text-to-image and image-to-image workflows. Compared with version 2.0, it is better suited for high-information-density images, complex compositions, and detail-rich visual scenes.

Model

agnes-image-2.1-flash

API Endpoint

POST /v1/images/generations

Core Optimization

High-information-density images, complex visual details, and semantic alignment.

Current Price

Image generation is currently $0 / image.

Overview

Agnes Image 2.1 Flash can generate images from text prompts and transform, redraw, or stylize input images. Results can be returned as image URLs or Base64 data.

High-density Visuals

Better suited for complex scenes, rich compositions, and multi-layer visual elements.

Composition Preservation

Preserves the original composition and subject layout as much as possible during image-to-image editing.

Core Capabilities

Text-to-image

Generate high-quality images from natural language prompts.

Image-to-image

Transform or improve existing images based on prompt instructions.

High-information-density Images

Optimized for detail-rich images with complex layouts and dense visual elements.

Composition Preservation

Preserve the original composition and subject layout when editing input images.

Flexible Size Control

Use resolution tiers such as 1K, 2K, 3K, or 4K with a supported aspect ratio.

URL / Base64 Output

Return generated images as URLs or Base64 data.

Use Cases

Creative Design

Concept art, visual exploration, and poster drafts.

Marketing Content

Campaign images, product visuals, and social media creatives.

High-density Visual Generation

Detailed scenes, complex environments, and rich compositions.

Image Transformation

Style transfer, scene relighting, and background transformation.

Product Visualization

Product photos, mockups, and commercial visuals.

Social Media Assets

Covers, banners, thumbnails, and post images.

API Reference

Endpoint

POST https://apihub.agnes-ai.com/v1/images/generations

Headers

-H "Authorization: Bearer YOUR_API_KEY"
-H "Content-Type: application/json"

Request Parameters

Parameter	Type	Required	Description
`model`	string	Yes	Model name. Use `agnes-image-2.1-flash`.
`prompt`	string	Yes	Text instruction for image generation or image editing.
`size`	string	Yes	Output size tier. Recommended values are `1K`, `2K`, `3K`, and `4K`. Legacy exact-size values such as `1024x768` are also accepted, but unsupported sizes may be normalized.
`ratio`	string	No	Aspect ratio used with tier-based `size`. Supported values include `1:1`, `3:4`, `4:3`, `16:9`, `9:16`, `2:3`, `3:2`, and `21:9`. Default is `1:1`.
`image`	string[]	Required for image-to-image	Input image array. Supports public image URLs or Data URI Base64.
`return_base64`	boolean	No	Use this when text-to-image output should be returned as Base64.
`extra_body`	object	No	Additional parameters for advanced workflows.
`extra_body.response_format`	string	No	Output format. Common values are `url` and `b64_json`.

Size and Ratio

For predictable output dimensions, use size together with ratio.

Recommended size values: 1K, 2K, 3K, 4K
Supported ratio values: 1:1, 3:4, 4:3, 16:9, 9:16, 2:3, 3:2, 21:9
If you request an unsupported exact size such as 1920x1080 or 2560x1440, the service may map it to the nearest supported tier and aspect ratio.
For common 16:9 display assets such as 1920x1080 or 2560x1440, request size: "2K" with ratio: "16:9" and then crop or resize downstream if you need an exact final canvas.

1920x1080 and 2560x1440 are standard display resolutions, but they are not the native output dimensions for this image model. When exact sizes are not supported, the response size may be normalized, for example to the 16:9 1K output size 1312x736.

Output Dimension Reference

Ratio	1K	2K	3K	4K
`1:1`	`1024x1024`	`2048x2048`	`3072x3072`	`4096x4096`
`3:4`	`864x1152`	`1728x2304`	`2592x3456`	`3456x4608`
`4:3`	`1152x864`	`2304x1728`	`3456x2592`	`4608x3456`
`16:9`	`1312x736`	`2624x1472`	`3936x2208`	`5248x2944`
`9:16`	`736x1312`	`1472x2624`	`2208x3936`	`2944x5248`
`2:3`	`832x1248`	`1664x2496`	`2496x3744`	`3328x4992`
`3:2`	`1248x832`	`2496x1664`	`3744x2496`	`4992x3328`
`21:9`	`1568x672`	`3136x1344`	`4704x2016`	`6272x2688`

Example: 16:9 2K Output

curl https://apihub.agnes-ai.com/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "agnes-image-2.1-flash",
    "prompt": "A cinematic product hero image for a desktop monitor wallpaper, clean lighting, high detail",
    "size": "2K",
    "ratio": "16:9",
    "extra_body": {
      "response_format": "url"
    }
  }'

This returns the 16:9 2K tier output size, 2624x1472.

Important Notes

Do not place response_format at the top level of the request body. For URL output, use extra_body.response_format: "url". For image-to-image Base64 output, use extra_body.response_format: "b64_json".

Text-to-image

Required parameters are model, prompt, and size.

Size + Ratio

Use tier-based size values such as 2K with ratio, for example 16:9.

Image-to-image

Provide an input image URL or Data URI Base64 value in extra_body.image.

Base64 Output

For text-to-image, use top-level return_base64: true.

No tags Required

Image-to-image requests do not require tags: ["img2img"].

Request Examples

Text-to-image: URL Output
Text-to-image: Base64 Output
Image-to-image: URL Input + URL Output
Image-to-image: Base64 Output
Data URI Base64 Input

curl https://apihub.agnes-ai.com/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "agnes-image-2.1-flash",
    "prompt": "A luminous floating city above a misty canyon at sunrise, cinematic realism",
    "size": "1024x768",
    "extra_body": {
      "response_format": "url"
    }
  }'

curl https://apihub.agnes-ai.com/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "agnes-image-2.1-flash",
    "prompt": "A clean product photo of a glass cube on a white studio background, soft shadows, high detail",
    "size": "1024x768",
    "return_base64": true
  }'

curl https://apihub.agnes-ai.com/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "agnes-image-2.1-flash",
    "prompt": "Transform the scene into a rain-soaked cyberpunk night with neon reflections while preserving the original composition",
    "size": "1024x768",
    "extra_body": {
      "image": [
        "https://example.com/input-image.png"
      ],
      "response_format": "url"
    }
  }'

curl https://apihub.agnes-ai.com/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "agnes-image-2.1-flash",
    "prompt": "Make the object orange while preserving the original composition",
    "size": "1024x768",
    "extra_body": {
      "image": [
        "https://example.com/input-image.png"
      ],
      "response_format": "b64_json"
    }
  }'

curl https://apihub.agnes-ai.com/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "agnes-image-2.1-flash",
    "prompt": "Make the object matte black while preserving the original composition",
    "size": "1024x768",
    "extra_body": {
      "image": [
        "data:image/png;base64,BASE64_HERE"
      ],
      "response_format": "b64_json"
    }
  }'

Response Format

URL Output
Base64 Output

{
  "created": 1780000000,
  "data": [
    {
      "url": "https://storage.googleapis.com/agnes-aigc/xxx.png",
      "b64_json": null,
      "revised_prompt": null
    }
  ]
}

Generated image URL path:

data[0].url

{
  "created": 1780000000,
  "data": [
    {
      "url": null,
      "b64_json": "iVBORw0KGgoAAAANSUhEUgAA...",
      "revised_prompt": null
    }
  ]
}

Generated Base64 image path:

data[0].b64_json

Response Fields

Field	Type	Description
`created`	integer	Request creation timestamp.
`data`	array	List of generated image results.
`data[].url`	string / null	Generated image URL. Usually `null` when using Base64 output.
`data[].b64_json`	string / null	Base64 image data. Usually `null` when using URL output.
`data[].revised_prompt`	string / null	Revised prompt if available. Otherwise `null`.

Prompting Guide

For better image generation results, use a clear prompt structure that describes the subject, environment, style, lighting, composition, and quality requirements.

Text-to-image Prompt Structure

[Subject] + [Scene / Environment] + [Style] + [Lighting] + [Composition] + [Quality Requirements]

A luminous floating city above a misty canyon at sunrise, cinematic realism, wide-angle composition, rich architectural details, soft golden light, high visual density

Image-to-image Prompt Structure

Clearly describe what should change and what should remain unchanged.

[Change Request] + [New Style / Scene] + [Elements to Add or Remove] + [Elements to Preserve]

Turn the daytime street scene into a cinematic cyberpunk night scene, add neon signs and wet road reflections, while preserving the original street layout, camera angle, and main building shapes.

High-information-density Images

Agnes Image 2.1 Flash is optimized for complex and detail-rich visuals. For best results, describe the visual hierarchy clearly.Recommended elements:

Main subject
Background environment
Important secondary details
Style and lighting
Composition constraints
Elements to preserve for image-to-image tasks

A large fantasy harbor city built on cliffs, hundreds of small boats, layered stone bridges, glowing windows, distant mountains, cloudy sunset sky, cinematic fantasy realism, wide-angle composition, rich architectural details, high visual density

Common Errors and Troubleshooting

Top-level response_format causes errors

Do not place response_format at the top level.Incorrect:

{
  "model": "agnes-image-2.1-flash",
  "prompt": "A futuristic city",
  "size": "1024x768",
  "response_format": "url"
}

Correct:

{
  "model": "agnes-image-2.1-flash",
  "prompt": "A futuristic city",
  "size": "1024x768",
  "extra_body": {
    "response_format": "url"
  }
}

Image-to-image does not require tags

Do not pass tags: ["img2img"]. Image-to-image only requires an input image array.

{
  "model": "agnes-image-2.1-flash",
  "prompt": "Make the object blue while preserving the original composition",
  "size": "1024x768",
  "extra_body": {
    "image": ["https://example.com/input.png"],
    "response_format": "url"
  }
}

Input image URL cannot be accessed

Use public HTTPS image URLs that do not require login, cookies, or private request headers. If the image cannot be made public, use Data URI Base64 input.

Request timeout

Image generation may take several seconds to tens of seconds depending on prompt complexity, image size, and server load. A client timeout of 60s - 360s is recommended.

Missing image parameter for image-to-image

Image-to-image generation requires an input image array in extra_body.image.

Pricing

Type	Standard Price	Current Price
Image generation	`$0.003 / image`	`$0 / image`

Integration Checklist

Use agnes-image-2.1-flash as the model name.

Use https://apihub.agnes-ai.com/v1/images/generations as the API endpoint.

For text-to-image, include model, prompt, and size.

For predictable dimensions, use size tiers such as 1K or 2K together with ratio.

For image-to-image, provide input images through extra_body.image.

Do not expose temporary or real API keys in public documentation.

Model

API Endpoint

Core Optimization

Current Price

​Overview

High-density Visuals

Composition Preservation

​Core Capabilities

Text-to-image

Image-to-image

High-information-density Images

Composition Preservation

Flexible Size Control

URL / Base64 Output

​Use Cases

Creative Design

Marketing Content

High-density Visual Generation

Image Transformation

Product Visualization

Social Media Assets

​API Reference

​Endpoint

​Headers

​Request Parameters

​Size and Ratio

​Output Dimension Reference

​Example: 16:9 2K Output

​Important Notes

Text-to-image

Size + Ratio

Image-to-image

Base64 Output

No tags Required

​Request Examples

​Response Format

​Response Fields

​Prompting Guide

​Common Errors and Troubleshooting

​Pricing

​Integration Checklist

Overview

Core Capabilities

Use Cases

API Reference

Endpoint

Headers

Request Parameters

Size and Ratio

Output Dimension Reference

Example: 16:9 2K Output

Important Notes

Request Examples

Response Format

Response Fields

Prompting Guide

Common Errors and Troubleshooting

Pricing

Integration Checklist