Claude Vision & Multimodal API Guide

Send images to Claude using the Anthropic API. Python and Node.js examples for base64 images, URLs, PDFs, and multi-image analysis. Works with Sonnet 4.6 and Haiku 4.5.

Claude's API supports multimodal inputs: you can pass images, PDFs, and text together in a single API call. Sonnet 4.6 and Haiku 4.5 both support vision. Opus 4.7 supports vision as well but is slower — for image-heavy workloads, Sonnet 4.6 is the sweet spot.

Python: analyze a local image (base64)

import anthropic, base64, pathlib

client = anthropic.Anthropic()

image_data = base64.standard_b64encode(pathlib.Path("diagram.png").read_bytes()).decode("utf-8")

message = client.messages.create(
    model="claude-sonnet-4-6",
    max_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": [
                {
                    "type": "image",
                    "source": {
                        "type": "base64",
                        "media_type": "image/png",
                        "data": image_data,
                    },
                },
                {"type": "text", "text": "Describe this diagram and list all labels."}
            ],
        }
    ],
)
print(message.content[0].text)

Python: image from URL

message = client.messages.create(
    model="claude-sonnet-4-6",
    max_tokens=512,
    messages=[
        {
            "role": "user",
            "content": [
                {
                    "type": "image",
                    "source": {
                        "type": "url",
                        "url": "https://example.com/chart.png",
                    },
                },
                {"type": "text", "text": "What trend does this chart show?"}
            ],
        }
    ],
)
print(message.content[0].text)

Python: multiple images in one call

def encode(path):
    return base64.standard_b64encode(pathlib.Path(path).read_bytes()).decode("utf-8")

message = client.messages.create(
    model="claude-sonnet-4-6",
    max_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": [
                {"type": "image", "source": {"type": "base64", "media_type": "image/png", "data": encode("before.png")}},
                {"type": "image", "source": {"type": "base64", "media_type": "image/png", "data": encode("after.png")}},
                {"type": "text", "text": "What changed between image 1 (before) and image 2 (after)?"}
            ],
        }
    ],
)
print(message.content[0].text)

Supported media types

• image/jpeg, image/png, image/gif, image/webp
• Max image size: 5 MB per image, up to 20 images per request
• PDF documents: pass as type: "document" with media_type: "application/pdf"

Node.js: analyze image

import Anthropic from "@anthropic-ai/sdk";
import { readFileSync } from "fs";

const client = new Anthropic();
const imageData = readFileSync("screenshot.png").toString("base64");

const response = await client.messages.create({
  model: "claude-sonnet-4-6",
  max_tokens: 512,
  messages: [
    {
      role: "user",
      content: [
        {
          type: "image",
          source: { type: "base64", media_type: "image/png", data: imageData }
        },
        { type: "text", text: "Extract all text visible in this screenshot." }
      ]
    }
  ]
});
console.log(response.content[0].text);

Token cost for images

Images are converted to tokens internally. A 1080×1080 image costs roughly 1,600–2,200 tokens depending on detail level. At Sonnet 4.6 rates ($3/M input tokens) that's ~$0.005 per image — negligible for batch pipelines.

Use the Claude Cost Calculator to model monthly costs for image-heavy workloads. The Prompt-Pricing Recommender can help you choose Haiku vs Sonnet for vision tasks.

Frequently asked questions

Free tools

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