Image thumbnail

Make a square thumbnail of an image - scales and center-crops to NxN (default 128). Send a base64 image and optional size. Returns the thumbnail. Deterministic, no network.

Input

Field	Type	Description
image *	string	base64 image, optionally a data: URL
size	number	square edge in px, 1-1024 (default 128)
format	string	output format: png (default), jpeg, bmp

Example output

{
  "__note": "returns the square thumbnail as binary"
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/image-thumbnail \
  -H "Content-Type: application/json" \
  -d '{"image":"iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJUlEQVR4AYXBAQEAIAyAMKSSnUxrJ99AtrXPfXxIkCBBggQJEgZ5JwJ01a+JcwAAAABJRU5ErkJggg==","size":128}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

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();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/image-thumbnail", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "image": "iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJUlEQVR4AYXBAQEAIAyAMKSSnUxrJ99AtrXPfXxIkCBBggQJEgZ5JwJ01a+JcwAAAABJRU5ErkJggg==",
    "size": 128
  }),
});

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits - a fraction of a second of CPU, no money, no AI tokens), 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-thumbnail")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/image-thumbnail", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"image":"iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJUlEQVR4AYXBAQEAIAyAMKSSnUxrJ99AtrXPfXxIkCBBggQJEgZ5JwJ01a+JcwAAAABJRU5ErkJggg==","size":128}) });

Part of these workflows

This tool is one step in 2 curated multi-tool workflows - agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• 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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