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How to analyze image with OpenAI GPT-4o

Q: How to analyze image with OpenAI GPT-4o

Use the gpt-4o model with OpenAI's Python SDK to analyze images by sending the image URL or base64 data in the messages array with image_url or image_base64 fields. The model returns a text analysis of the image content.

Quick answer

Use the gpt-4o model with OpenAI's Python SDK to analyze images by sending the image URL or base64 data in the messages array with image_url or image_base64 fields. The model returns a text analysis of the image content.

PREREQUISITES

Python 3.8+
OpenAI API key (free tier works)
pip install openai>=1.0

Setup

Install the OpenAI Python SDK and set your API key as an environment variable.

bash

pip install openai>=1.0

Step by step

This example sends an image URL to gpt-4o for analysis and prints the textual description returned by the model.

python

import os
from openai import OpenAI

client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])

messages = [
    {
        "role": "user",
        "content": "Analyze the content of this image.",
        "image_url": {
            "url": "https://images.unsplash.com/photo-1506744038136-46273834b3fb"
        }
    }
]

response = client.chat.completions.create(
    model="gpt-4o",
    messages=messages
)

print(response.choices[0].message.content)

output

A scenic photo showing a mountain landscape with a clear blue sky and some clouds, featuring lush greenery in the foreground.

Common variations

Use image_base64 instead of image_url to send images encoded in base64.
Switch to gpt-4o-mini for faster, cheaper analysis with slightly reduced accuracy.
Use async calls with asyncio for concurrent image analysis.

python

import os
import asyncio
from openai import OpenAI

async def analyze_image():
    client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
    messages = [
        {
            "role": "user",
            "content": "Describe this image.",
            "image_url": {"url": "https://images.unsplash.com/photo-1506744038136-46273834b3fb"}
        }
    ]
    response = await client.chat.completions.acreate(
        model="gpt-4o",
        messages=messages
    )
    print(response.choices[0].message.content)

asyncio.run(analyze_image())

output

A scenic photo showing a mountain landscape with a clear blue sky and some clouds, featuring lush greenery in the foreground.

Troubleshooting

If you get an authentication error, verify your OPENAI_API_KEY environment variable is set correctly.
If the image is not analyzed, ensure the URL is publicly accessible and uses HTTPS.
For large images, consider resizing or compressing before sending to avoid timeouts.

✅

Key Takeaways

Use gpt-4o with image_url or image_base64 in messages to analyze images.
Always set your API key in os.environ["OPENAI_API_KEY"] for secure authentication.
Async calls enable efficient batch image analysis with the OpenAI Python SDK.
Ensure images are accessible via HTTPS URLs or properly encoded base64 strings.
Use smaller or compressed images to avoid request timeouts or errors.

Verified 2026-04 · gpt-4o, gpt-4o-mini

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