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POST
/
v1
/
images
/
generations
curl --request POST \ --url https://api.evolink.ai/v1/images/generations \ --header 'Authorization: Bearer <token>' \ --header 'Content-Type: application/json' \ --data ' { "model": "gpt-image-2", "prompt": "A beautiful colorful sunset over the ocean" } '
{
  "created": 1757156493,
  "id": "task-unified-1757156493-imcg5zqt",
  "model": "gpt-image-2",
  "progress": 0,
  "status": "pending",
  "task_info": {
    "can_cancel": true,
    "estimated_time": 100
  },
  "type": "image",
  "usage": {
    "billing_rule": "per_call",
    "credits_reserved": 2.5,
    "user_group": "default"
  }
}

Authorizations

​
Authorization
string
header
required

##All APIs require Bearer Token authentication##

Get API Key:

Visit API Key Management Page to get your API Key

Add to request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json
​
model
enum<string>
default:gpt-image-2
required

Image generation model name, official channel, better stability and controllability, suitable for commercial scenarios

Available options:
gpt-image-2
Example:

"gpt-image-2"

​
prompt
string
required

Prompt describing the image to be generated, or describing how to edit the input image

Limits:

  • Up to 32000 characters (counted by Unicode code points, works for CJK and other languages)
Maximum string length: 32000
Example:

"A beautiful colorful sunset over the ocean"

​
image_urls
string<uri>[]

Reference image URL list for image-to-image and image editing functions

Note:

  • Number of input images per request: 1~16
  • Size of a single image: not exceeding 50MB
  • Supported file formats: .jpeg, .jpg, .png, .webp
  • Image URLs must be directly accessible by the server, or the image URL should directly download when accessed (typically these URLs end with image file extensions, such as .png, .jpg)
  • In image-to-image / image editing scenarios, the reference images themselves also incur additional image input token consumption
Example:
[
  "https://example.com/image1.png",
  "https://example.com/image2.png"
]
​
mask_url
string<uri>

Inpainting mask URL — marks the region of the reference image to regenerate. Only valid in image edit mode (must be combined with image_urls); the mask is silently ignored in pure text-to-image requests.

Format requirements:

  • Must be a PNG with an alpha channel: transparent pixels (alpha < 255) = regions to regenerate; opaque pixels = preserved
  • Mask dimensions must exactly match the reference image dimensions (width × height in pixels)
  • Single mask per request

Note:

  • At least one reference image is required in image_urls; a mask sent alone has no effect
  • Common errors:
    • Invalid mask image format - mask image missing alpha channel: the uploaded image has no alpha channel (JPEG, opaque PNG, etc.). Re-export the mask as a PNG with transparent regions.
    • Invalid mask image format - mask size does not match image size: the mask dimensions don't match the reference image. Resize the mask to the same pixel dimensions as your reference image.
Example:

"https://example.com/mask.png"

​
size
string
default:auto

Size of the generated image. Supports both ratio format and explicit pixel format, defaults to auto

① Ratio format (recommended, 15 options)

  • 1:1: Square
  • 1:2 / 2:1: Extreme portrait / landscape
  • 1:3 / 3:1: Ultra portrait / landscape (3:1 limit)
  • 2:3 / 3:2: Standard portrait / landscape
  • 3:4 / 4:3: Classic portrait / landscape
  • 4:5 / 5:4: Common social media
  • 9:16 / 16:9: Mobile / desktop widescreen
  • 9:21 / 21:9: Ultra-wide

② Explicit pixel format: WxH (or W×H), e.g. 1024x1024, 1536x1024, 3840×2160

  • Both width and height must be multiples of 16
  • Each edge range: [16, 3840]
  • Pixel budget: 655,360 ≤ width × height ≤ 8,294,400 (about 0.65 MP ~ 8.29 MP)
  • Aspect ratio: ≤ 3:1

③ auto: The model decides the size automatically (resolution does not apply in this mode)

Out-of-range handling:

  • If a ratio + resolution combination exceeds the pixel budget, dimensions are automatically scaled down proportionally (e.g. 4K 2:1 → 3840×1920)
Example:

"auto"

​
resolution
enum<string>
default:1K

Resolution tier shortcut, only effective when size is a ratio; ignored in explicit pixel mode

Pixel budget rules (dimensions are derived from the target pixel count and the size ratio, aligned to multiples of 16):

  • 1K: ~1 MP (1024² = 1,048,576 pixels)
  • 2K: ~4 MP (2048² = 4,194,304 pixels)
  • 4K: ~8.29 MP (3840×2160 = 8,294,400 pixels, the maximum)

Landscape / square output dimensions (portrait dimensions are the landscape width/height swapped, e.g. 2:3 = 3:2 reversed):

Ratio1K2K4K
1:11024×10242048×20482880×2880
2:11456×7202896×14563840×1920 *
3:11776×5923552×11843840×1280 *
3:21248×8322512×16803520×2352
4:31184×8802368×17763312×2480 *
5:41152×9122288×18243216×2576
16:91360×7682736×15363840×2160 (UHD)
21:91568×6723136×13443840×1632 *

* Marks combinations that are auto-downscaled to fit the pixel budget. Values are case-insensitive.

Available options:
1K,
2K,
4K
Example:

"1K"

​
quality
enum<string>
default:medium

Rendering quality that controls the model's "reasoning depth", directly affecting output token count and cost. Defaults to medium

ValueTile baseRelative cost (1024²)
low16~0.11×
medium481.0×
high96~4.0×
Available options:
low,
medium,
high
Example:

"medium"

​
n
integer
default:1

Number of images to generate, each billed independently

Note:

  • Text input tokens scale linearly with n
Required range: 1 <= x <= 10
Example:

1

​
callback_url
string<uri>

HTTPS callback address after task completion

Callback Timing:

  • Triggered when task is completed, failed, or cancelled
  • Sent after billing confirmation is completed

Security Restrictions:

  • Only HTTPS protocol is supported
  • Callback to internal IP addresses is prohibited (127.0.0.1, 10.x.x.x, 172.16-31.x.x, 192.168.x.x, etc.)
  • URL length must not exceed 2048 characters

Callback Mechanism:

  • Timeout: 10 seconds
  • Maximum 3 retries on failure (retries after 1 second/2 seconds/4 seconds)
  • Callback response body format is consistent with the task query API response format
  • Callback address returning 2xx status code is considered successful, other status codes will trigger retry
Example:

"https://your-domain.com/webhooks/image-task-completed"

Response

Image generation task created successfully

​
created
integer

Task creation timestamp

Example:

1757156493

​
id
string

Task ID

Example:

"task-unified-1757156493-imcg5zqt"

​
model
string

Actual model name used

Example:

"gpt-image-2"

​
object
enum<string>

Specific task type

Available options:
image.generation.task
​
progress
integer

Task progress percentage (0-100)

Required range: 0 <= x <= 100
Example:

0

​
status
enum<string>

Task status

Available options:
pending,
processing,
completed,
failed
Example:

"pending"

​
task_info
object

Asynchronous task information

​
type
enum<string>

Task output type

Available options:
text,
image,
audio,
video
Example:

"image"

​
usage
object

Usage and billing information