Image Generations

Some of the models can provide image generation capabilities. You can provide some descriptions of the image you would like to generate, and let the model generate one or multiple pictures in the output.

If you're used to interacting with the chat/image-understanding models, the image generation is a bit different from them. You only need to send a prompt text in the request, instead of a list of messages with system/user/assistant roles. When you sent the prompt for image generation, your prompt will be revised by a chat model, and then sent to the image generation model.

Parameters

n: Number of image(s) to generate (1-10, default to 1)

response_format: "url" or "b64_json". If "url" is specified, the response will return a url to the image(s) in data[index].url; if "b64_json" is specified, the response will return the image(s) in base64 encoded format in data[index].b64_json.

Note: quality, size or style are not supported by xAI API at the moment.

Request BodyExpand AllpromptstringrequiredPrompt for image generation.Show optional fields

Generate image

The image generation is offered at a different endpoint https://api.x.ai/v1/images/generations from the chat and image-understanding models that share https://api.x.ai/v1/chat/completions. The endpoint is compatible with OpenAI SDK (but not with Anthropic SDK), so you can keep using the same base_url of https://api.x.ai/v1.

You can set "model": "grok-2-image" in the request body to use the model. The generated image will be in jpg format.

bash

curl -X 'POST' https://api.x.ai/v1/images/generations \ -H 'accept: application/json' \ -H 'Authorization: Bearer <API_KEY>' \ -H 'Content-Type: application/json' \ -d '{ -d '{  "model": "grok-2-image",  "prompt": "A cat in a tree" }'

The Python and JavaScript examples will print out url of the image on xAI managed storage.

This is an example image generated from the above prompt:

1a9d1139d479c4e156cb73d26bd08e56_example-cat-in-tree.png

Base 64 JSON Output

Instead of getting an image url by default, you can choose to get a base64 encoded image instead. To do so, you need to specify the response_format parameter to "b64_json".

You will get a b64_json field instead of url in the response image object.

Generating multiple images

You can generate up to 10 images in one request by adding a parameter n in your request body. For example, to generate four images:

Revised prompt

If you inspect the response object, you can see something similar to this:

{
    "data": [
        {
            "b64_json": "data:image/png;base64,...",
            "revised_prompt": "..."
        }
    ]
}

Before sending the prompt to the image generation model, the prompt will be revised by a chat model. The revised prompt from chat model will be used by image generation model to create the image, and returned in revised_prompt to the user.

To see the revised prompt with OpenAI SDK:

For example:

Input/Output	Example
prompt (in request body)	A cat in a tree
revised_prompt (in response body)	3D render of a gray cat with green eyes perched on a thick branch of a leafy tree, set in a suburban backyard during the day. The cat's fur is slightly ruffled by a gentle breeze, and it is looking directly at the viewer. The background features a sunny sky with a few clouds and other trees, creating a natural and serene environment. The scene is focused on the cat, with no distracting foreground elements, ensuring the cat remains the central subject of the image.

Input/Output

Example

prompt (in request body)

A cat in a tree

revised_prompt (in response body)

3D render of a gray cat with green eyes perched on a thick branch of a leafy tree, set in a suburban backyard during the day. The cat's fur is slightly ruffled by a gentle breeze, and it is looking directly at the viewer. The background features a sunny sky with a few clouds and other trees, creating a natural and serene environment. The scene is focused on the cat, with no distracting foreground elements, ensuring the cat remains the central subject of the image.

Image Generations

Parameters#

Generate image#

Base 64 JSON Output#

Generating multiple images#

Revised prompt#

Request

Responses

Parameters

Generate image

Base 64 JSON Output

Generating multiple images

Revised prompt