gchq/CyberChef · error · OperationError

Invalid file type.

Error message

Invalid file type.

What it means

Crop Image performs a manual crop (x, y, width, height) or an autocrop. It validates the input via isImage() first; non-image bytes cause `if (!isImage(input))` to throw 'Invalid file type.' This is the magic-byte input check before Jimp decoding.

Source

Thrown at src/core/operations/CropImage.mjs:107

    /**
     * @param {ArrayBuffer} input
     * @param {Object[]} args
     * @returns {byteArray}
     */
    async run(input, args) {
        const [
            xPos,
            yPos,
            width,
            height,
            autocrop,
            autoTolerance,
            autoFrames,
            autoSymmetric,
            autoBorder,
        ] = args;
        if (!isImage(input)) {
            throw new OperationError("Invalid file type.");
        }

        let image;
        try {
            image = await Jimp.read(input);
        } catch (err) {
            throw new OperationError(`Error loading image. (${err})`);
        }
        try {
            if (isWorkerEnvironment())
                self.sendStatusMessage("Cropping image...");
            if (autocrop) {
                image.autocrop({
                    tolerance: autoTolerance / 100,
                    cropOnlyFrames: autoFrames,
                    cropSymmetric: autoSymmetric,
                    leaveBorder: autoBorder,
                });

View on GitHub (pinned to 4290ea7539)

Solutions

1. Supply a raw image ArrayBuffer isImage recognizes.
2. Decode hex/base64 input with From Hex / From Base64 first.
3. Confirm with Detect File Type before cropping.

Example fix

// before: passing hex text directly
input = "89504e47...";
// after
recipe: [From Hex, Crop Image]

import { isImage } from "src/core/lib/FileType.mjs";
const bytes = input instanceof ArrayBuffer ? new Uint8Array(input) : input;
if (!isImage(bytes)) {
  throw new Error("Input is not a recognized image; supply raw image bytes.");
}

import { isImage } from "src/core/lib/FileType.mjs";
function isImageInput(buf) {
  const bytes = buf instanceof ArrayBuffer ? new Uint8Array(buf) : buf;
  return isImage(bytes) !== false;
}

When it happens

Trigger: Non-image bytes; truncated file missing magic bytes; empty ArrayBuffer; a format absent from isImage's signature table; passing a string instead of raw bytes.

Common situations: Wrong input; chaining after a non-image-producing op; forgetting to decode hex/base64; unsupported image format.

Related errors

• Invalid file type.
• Invalid file format.
• Invalid file type.
• Invalid file type.
• Error loading image. (${err})

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/861bcfb443650256. Report an issue: GitHub.