# Generate Images with the OpenAI API (gpt-image)

> Two ways to make an image with the OpenAI API — the Images endpoint and the image_generation tool — save the PNG, set size, quality and format.

- Canonical: https://guides-ai.pages.dev/guides/openai-api-image-generation/
- Plate 15.16 · Topic: Building with the API (https://guides-ai.pages.dev/topics/api/)
- Published: 06 Sept 2026 · 3 min read
- Source site: guides-ai — https://guides-ai.pages.dev/

There are two doors to the same models. The **Images API** is the direct one: prompt in, image out. The **Responses API** lets a chat model decide to call an `image_generation` tool as part of a conversation, so you can refine an image in follow-up turns.

## 1. Key

```bash
export OPENAI_API_KEY="sk-..."   # macOS/Linux; PowerShell: $env:OPENAI_API_KEY="sk-..."
pip install openai
```

Both SDK calls below read the key from the environment.

## 2. Images API: prompt in, PNG out

```python
from openai import OpenAI
import base64

client = OpenAI()

result = client.images.generate(
    model="gpt-image-2",
    prompt="A children's book drawing of a veterinarian using a stethoscope to listen to the heartbeat of a baby otter.",
)

with open("otter.png", "wb") as f:
    f.write(base64.b64decode(result.data[0].b64_json))
```

Returns the image as base64 in `data[0].b64_json`; decoding it and writing the bytes gives you a PNG. `gpt-image-2` is the current model; `gpt-image-1.5`, `gpt-image-1` and `gpt-image-1-mini` are the cheaper/older options.

## 3. Responses API: the model generates as a tool

```python
from openai import OpenAI
import base64

client = OpenAI()

response = client.responses.create(
    model="gpt-6-astra",
    input="Generate an image of a gray tabby cat hugging an otter with an orange scarf",
    tools=[{"type": "image_generation"}],
)

images = [o.result for o in response.output if o.type == "image_generation_call"]
if images:
    with open("otter.png", "wb") as f:
        f.write(base64.b64decode(images[0]))
```

The text model plans the prompt and calls the tool; the image comes back as an `image_generation_call` output item with base64 in `result`. Continue the same conversation ("make the scarf blue") to edit it.

## 4. The knobs

```python
result = client.images.generate(
    model="gpt-image-2",
    prompt="Flat vector icon of a paper plane, single color, transparent background",
    size="1024x1024",        # or 1536x1024, 1024x1536, auto
    quality="high",          # low, medium, high, auto
    output_format="png",     # png (default), jpeg, webp
    background="transparent" # transparent, opaque, auto
)
```

`n` makes several images per call; `output_compression` (0–100) shrinks JPEG/WebP; `moderation="low"` relaxes the content filter — blocked requests come back as a `moderation_blocked` error.

## 5. Edits

The edits endpoint takes an input image (and optionally a mask marking the region to replace) plus a prompt, and returns the modified image in the same base64 shape. It's the route for "same picture, change one thing"; for a new picture, generate again.

---

Next: [your first OpenAI API request](/guides/openai-api-first-request/) · [generate images locally with FLUX](/guides/generate-images-with-flux-locally/).