Image resize

Resize an image to given pixel dimensions. Send POST /api/image-resize with the required field image and pay $0.001 per call over x402 or MPP, or call it free by solving a proof-of-work challenge. It returns raw bytes, not JSON, with Content-Type image/png, image/jpeg or image/bmp.

Send a base64 PNG/JPEG/BMP and width and/or height (give one to scale proportionally). Returns the resized image. Deterministic, no network.

Category: Web & documents · Tags: image resize scale thumbnail png jpeg

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/image-resize \
  -H "Content-Type: application/json" \
  -d '{"image":"iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJUlEQVR4AYXBAQEAIAyAMKSSnUxrJ99AtrXPfXxIkCBBggQJEgZ5JwJ01a+JcwAAAABJRU5ErkJggg==","width":256}'

Without payment this returns HTTP 402 Payment Required with the exact price for image-resize; any x402 v2 or MPP client pays it and retries.

Example response

A 200 carries raw bytes, not JSON, with Content-Type image/png, image/jpeg or image/bmp: the file itself.

From an MCP client

catalog.call {
  "slug": "image-resize",
  "params": {
    "image": "iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJUlEQVR4AYXBAQEAIAyAMKSSnUxrJ99AtrXPfXxIkCBBggQJEgZ5JwJ01a+JcwAAAABJRU5ErkJggg==",
    "width": 256
  }
}

On the hosted connector at https://agent402.tools/mcp, catalog.call runs image-resize free (rate-limited, no wallet). Local install: npx -y agent402-mcp.

Errors and behavior

• image is required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Free tier: no outbound network call leaves the server for this tool, so proof-of-work (16 leading zero bits of sha256) pays for it.
• A GET or HEAD to /api/image-resize returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header does not replay this tool's answer: the replay cache holds JSON answers only, so a retried paid call runs and is charged again.

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/image-resize", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "image": "iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJUlEQVR4AYXBAQEAIAyAMKSSnUxrJ99AtrXPfXxIkCBBggQJEgZ5JwJ01a+JcwAAAABJRU5ErkJggg==",
    "width": 256
  }),
});

No wallet? Pay with compute

Fetch a challenge, solve the sha256 puzzle (16 leading zero bits, a fraction of a second of CPU), and resend with the X-Pow-Solution header:

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=image-resize")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/image-resize", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"image":"iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJUlEQVR4AYXBAQEAIAyAMKSSnUxrJ99AtrXPfXxIkCBBggQJEgZ5JwJ01a+JcwAAAABJRU5ErkJggg==","width":256}) });

Part of these workflows

Image resize is one step in these 2 skill packs, each sold as a single call:

• Uploaded-media normalize - The 'user uploaded a thing, normalize it before storing' workflow. Probe the file (image or audio/video) with media-info, decode any embedded barcodes/QRs, resize and thumbnail the image, convert it to a web-friendly format, and normalize audio loudness to broadcast standard. Six tools, one canonical normalize-on-upload pipeline that turns arbitrary user uploads into predictable storage artifacts.
• Link preview card - The 'turn a URL into a card-shaped preview' workflow. Pull OpenGraph/Twitter card metadata, fetch the article body as a description fallback, normalize the og:image into a standard 1200×630 social card variant and a 400×400 square thumbnail, and extract URL/mention entities from the body for related-link surfacing. Five tools, one structured card payload ready for chat embeds, social shares, or RSS-to-card pipelines.

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