This guide shows how to generate images using GPT Image-2.0 model via the Leonardo.AI REST API.

Sample Request

curl --location 'https://cloud.leonardo.ai/api/rest/v2/generations' \
     --header 'authorization: Bearer {api-key}' \
     --header 'Content-Type: application/json' \
     --data '{
       "public": false,
       "model": "gpt-image-2",
       "parameters": {
           "quality": "MEDIUM",
           "prompt": "Koala with purple hat",
           "quantity": 2,
           "width": 1376,
           "height": 768,
           "prompt_enhance": "OFF",
           "guidances": {
               "image_reference": [
                   {
                       "image": {
                         "id": "00000000-0000-0000-0000-000000000001",
                         "type": "UPLOADED"
                       }
                   }
               ]
           }
        }
     }'

Recipe

API Request Endpoint, Headers, Parameters

Endpoint

https://cloud.leonardo.ai/api/rest/v2/generations

Headers

--header "accept: application/json" \
--header "authorization: Bearer <YOUR_API_KEY>" \
--header "content-type: application/json"

Body Parameters

Parameter	Type	Definition
guidances	`object`	Optional. Object defining image guidance inputs that influence the generated result.
guidances.image_reference	`array`	Optional. Array of up to 6 reference images. Each reference includes image.id, image.type (`GENERATED` or `UPLOADED`). Note: GPT Image 2 does not use `strength` for image references.
height	`integer`	Optional. Height input resolution.
model	`string`	Required. Model identifier. Set to `gpt-image-2`.
prompt	`string`	Required. Text prompt describing what image you want the model to generate.
prompt_enhance	`string`	Optional. Enables prompt enhancement when set to `"ON"`; disabled when set to `"OFF"`.
public	`boolean`	Optional. Boolean flag that determines whether the generation is public (`true`) or private (`false`).
quality	`string`	Optional. Accepts `LOW`, `MEDIUM`, or `HIGH`.
quantity	`integer`	Optional. Number of images to generate in a single request (1-8).
width	`integer`	Optional. Width input resolution.

Aspect Ratio Settings

Aspect Ratio	Width	Height
1:1	1024	1024
2:3	848	1264
3:2	1264	848
16:9	1376	768
9:16	768	1376

Resolution Constraints

GPT Image 2 supports flexible custom resolutions with the following constraints:

Max edge length
max(width, height) < 3840
Multiple of 16
Both width and height must be multiples of 16.
Aspect ratio limit
Let long = max(width, height) and short = min(width, height).
long / short ≤ 3
(No aspect ratio wider than 3:1 or taller than 1:3.)
Pixel count range
655,360 ≤ width × height ≤ 8,294,400
No auto sizing
size: "auto" is not supported and must not be passed to the API.