Generating Images with AWS Bedrock Stable Image Core

The Bedrock Client

AWS Bedrock is accessed via boto3. The image model runs in us-west-2 — the only region where Stable Image Core was available at time of writing.

import boto3, base64, json
from decouple import config

def _bedrock_client():
    return boto3.client(
        "bedrock-runtime",
        region_name="us-west-2",
        aws_access_key_id=config("AWS_ACCESS_KEY_ID"),
        aws_secret_access_key=config("AWS_SECRET_ACCESS_KEY"),
    )

Invoking the Model

The model ID is stability.stable-image-core-v1:1. The payload is a JSON body with the prompt and output format; the response contains the generated image as a base64 string inside a images list.

IMAGE_MODEL = "stability.stable-image-core-v1:1"

def generate_image(prompt: str) -> bytes:
    client   = _bedrock_client()
    response = client.invoke_model(
        modelId=IMAGE_MODEL,
        contentType="application/json",
        accept="application/json",
        body=json.dumps({
            "prompt":        prompt,
            "aspect_ratio":  "1:1",
            "output_format": "png",
        }),
    )
    body = json.loads(response["body"].read())
    return base64.b64decode(body["images"][0])

Storing in S3

The image bytes are uploaded directly to S3 using put_object. The resulting URL is stored alongside the user's media record.

import uuid

def save_to_s3(image_bytes: bytes, user_id: int) -> str:
    s3     = boto3.client("s3", region_name=config("AWS_S3_REGION_NAME"))
    key    = f"ai-generated/{user_id}/{uuid.uuid4()}.png"
    bucket = config("AWS_STORAGE_BUCKET_NAME")
    region = config("AWS_S3_REGION_NAME")

    s3.put_object(
        Bucket=bucket,
        Key=key,
        Body=image_bytes,
        ContentType="image/png",
    )
    return f"https://{bucket}.s3.{region}.amazonaws.com/{key}"