gchq/CyberChef · error · OperationError

Error generating image. (${err})

Error message

Error generating image. (${err})

What it means

Thrown by GenerateImage when Jimp's async getBuffer(JimpMime.png) fails during PNG encoding of the generated image. The underlying error is interpolated. PNG encoding can fail due to malformed image state, memory limits, or Jimp internal errors.

Source

Thrown at src/core/operations/GenerateImage.mjs:181

        if (scale !== 1) {
            if (isWorkerEnvironment())
                self.sendStatusMessage("Scaling image...");

            image.scaleToFit({
                w: width * scale,
                h: height * scale,
                mode: ResizeStrategy.NEAREST_NEIGHBOR,
            });
        }

        try {
            // see https://nodejs.org/docs/latest-v24.x/api/buffer.html#bufbyteoffset
            // for why we can't just return result.buffer
            const result = await image.getBuffer(JimpMime.png);
            return result.buffer.slice(result.byteOffset, result.byteOffset + result.byteLength);
        } catch (err) {
            throw new OperationError(`Error generating image. (${err})`);
        }
    }

    /**
     * Displays the generated image using HTML for web apps
     * @param {ArrayBuffer} data
     * @returns {html}
     */
    present(data) {
        if (!data.byteLength) return "";
        const dataArray = new Uint8Array(data);

        const type = isImage(dataArray);
        if (!type) {
            throw new OperationError("Invalid file type.");
        }

        return `<img src="data:${type};base64,${toBase64(dataArray)}">`;

View on GitHub (pinned to 4290ea7539)

Solutions

1. Check that the input is non-empty and produces a positive width/height (width arg > 0 and input length > 0).
2. Inspect the interpolated err for the Jimp-specific cause.
3. Verify the Jimp dependency version matches what the operation expects.

if (!input.length || width < 1) {
  // avoid degenerate image; do not call getBuffer
}

try {
  const result = await image.getBuffer(JimpMime.png);
  return result.buffer.slice(result.byteOffset, result.byteOffset + result.byteLength);
} catch (err) {
  throw new OperationError(`Error generating image. (${err})`);
}

When it happens

Trigger: An image with zero width or height (e.g. empty input), a Jimp internal error during buffer serialization, or an environment where the PNG encoder is unavailable/corrupted.

Common situations: Empty or near-empty input producing a degenerate image, or a Jimp dependency version mismatch in a Node packaging context.

Related errors

• Error blurring image. (${err})
• Error while generating image from pixel values. (${err})
• Error loading image. (${err})
• Error opening image. (${err})
• Error normalising image. (${err})

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/bd784a76c7e9a591. Report an issue: GitHub.