gchq/CyberChef · error · OperationError

Invalid file type.

Error message

Invalid file type.

What it means

Thrown by ResizeImage when isImage() does not recognize the input as a supported image format. The check runs before Jimp.read, so non-image or unsupported-format input is rejected early.

Source

Thrown at src/core/operations/ResizeImage.mjs:91

     * @returns {byteArray}
     */
    async run(input, args) {
        let width = args[0],
            height = args[1];
        const unit = args[2],
            aspect = args[3],
            resizeAlg = args[4];

        const resizeMap = {
            "Nearest Neighbour": ResizeStrategy.NEAREST_NEIGHBOR,
            Bilinear: ResizeStrategy.BILINEAR,
            Bicubic: ResizeStrategy.BICUBIC,
            Hermite: ResizeStrategy.HERMITE,
            Bezier: ResizeStrategy.BEZIER,
        };

        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 (unit === "Percent") {
                width = image.width * (width / 100);
                height = image.height * (height / 100);
            }

            if (isWorkerEnvironment())
                self.sendStatusMessage("Resizing image...");
            if (aspect) {
                image.scaleToFit({

View on GitHub (pinned to 4290ea7539)

Solutions

1. Provide a supported raster image (PNG/JPEG/GIF/BMP).
2. Convert HEIC/WebP/other to PNG or JPEG first.
3. Ensure encoded input is decoded (From Base64/From Hex) before this operation.
4. Verify the file is not truncated.

Example fix

// before
//   input: HEIC bytes (unsupported)
// after
//   input: same image converted to PNG

if (!isImage(input)) throw new Error('Input is not a supported image');

const isSupportedImage = buf => Boolean(isImage(buf));

try { await resizeImage(input); } catch (e) { if (/Invalid file type/.test(e.message)) convertToPng(input); else throw e; }

When it happens

Trigger: Non-image bytes; corrupted/truncated image; an unsupported format (e.g. some HEIC/WebP variants); wrong upstream decoding.

Common situations: Piping non-image output into ResizeImage; uploading an obscure format; truncated copy-paste; missing 'From Base64' step.

Related errors

• Error opening image. (${err})
• Invalid file type.
• Error containing image. (${err})
• Error covering image. (${err})
• Please enter a valid image file.

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/b46bdde9ddef7dba. Report an issue: GitHub.