MODULE_NOT_FOUND in deployment during function call, but not in development

Question

I am building a website that can identify a seiko-watch based on an image, using tfjs-node on the backend. I built a custom node package for it to use, which works great tfjs-image-node. The frontend takes an image and sends it to the backend as data64, the backend then uploads the image to cloudinary and takes that url and uses tfjs-image-node to get the prediction.

Everything works great in production, and even when it is built, and I preview it - but as soon as I deploy the app on vercel, I get an Error: Cannot find module 'jimp'. Jimp is used in the tfjs-image-node package, and is set as a dependency, not a devDependency.

Code

Seiko Identifier api/identify

export async function POST(req: NextRequest) {
  try {
    const body = await req.json();
    const image = body.image;
    if (image.length === 0)
      return NextResponse.json(
        { message: "ERR_MISSING_IMAGE" },
        { status: 400 }
      );

    const img = await cloudinary.uploader.upload(
      image,
      (error: any, result: any) => {
        if (error) {
          return NextResponse.json(error, { status: 500 });
        }
        return NextResponse.json(result);
      }
    );

    const result: IResult[] | Error = await classifyImage(modelURL, img.url, "regular");

    if (result instanceof Array) {
      return NextResponse.json(result[0], { status: 200 });
    } else {
      return NextResponse.json({}, { status: 500 });
    }
  } catch (error) {
    return NextResponse.json(error, { status: 500 });
  }
}

TFJS-image-node

    if (!MODEL_DIR_PATH || !IMAGE_FILE_PATH) {
        return new Error("MISSING_PARAMETER");
    }

    let labels: string[];

    if (!METADATA) {
        const res = await fetch(`${MODEL_DIR_PATH}/metadata.json`);
        if (res.status !== 200) {
            return new Error("METADATA_NOT_FOUND" + res);
        } else {
            const json = await res.json();
            labels = json["labels"];
        }
    } else {
        labels = METADATA["labels"];
    }

    const model = await tf.loadLayersModel(`${MODEL_DIR_PATH}/model.json`);

    const image = await Jimp.read(IMAGE_FILE_PATH);
    image.cover(224, 224, Jimp.HORIZONTAL_ALIGN_CENTER | Jimp.VERTICAL_ALIGN_MIDDLE);

    const NUM_OF_CHANNELS = 3;
    let values = new Float32Array(224 * 224 * NUM_OF_CHANNELS);

    let i = 0;
    image.scan(0, 0, image.bitmap.width, image.bitmap.height, (x: number, y: number) => {
        const pixel = Jimp.intToRGBA(image.getPixelColor(x, y));
        pixel.r = pixel.r / 127.0 - 1;
        pixel.g = pixel.g / 127.0 - 1;
        pixel.b = pixel.b / 127.0 - 1;
        pixel.a = pixel.a / 127.0 - 1;
        values[i * NUM_OF_CHANNELS + 0] = pixel.r;
        values[i * NUM_OF_CHANNELS + 1] = pixel.g;
        values[i * NUM_OF_CHANNELS + 2] = pixel.b;
        i++;
    });

    const outShape = [224, 224, NUM_OF_CHANNELS];
    let img_tensor = tf.tensor3d(values, outShape, "float32");
    img_tensor = img_tensor.expandDims(0);

    const predictions = await model.predict(img_tensor).dataSync();

    let result: ResultType[] = [];

    for (let i = 0; i < predictions.length; i++) {
        const label = labels[i];
        const probability = predictions[i];
        result.push({ label: label, probability: probability });
    }

    return result.sort((a, b) => Number(b.probability) - Number(a.probability));

Expected

Expected

Actual

Actual

Error: Cannot find module 'jimp'
Require stack:
- /var/task/.next/server/app/api/identify/route.js
- /var/task/node_modules/next/dist/compiled/next-server/server.runtime.prod.js
- /var/task/___next_launcher.cjs
        at Module._resolveFilename (node:internal/modules/cjs/loader:1048:15)
        at /var/task/node_modules/next/dist/compiled/next-server/server.runtime.prod.js:11:25599
        at Module._load (node:internal/modules/cjs/loader:901:27)
        at r.<computed>.e._load (/var/task/___vc/__launcher/__launcher.js:14:2516)
        at Module.require (node:internal/modules/cjs/loader:1115:19)
        at w.require (/var/task/node_modules/next/dist/compiled/next-server/server.runtime.prod.js:11:25815)
        at require (node:internal/modules/helpers:130:18)
        at 92622 (/var/task/.next/server/app/api/identify/route.js:1:3312)
        at t (/var/task/.next/server/webpack-runtime.js:1:143)
        at r (/var/task/.next/server/app/api/identify/route.js:38:271137) {
    code: 'MODULE_NOT_FOUND',
    requireStack: [
        '/var/task/.next/server/app/api/identify/route.js',
        '/var/task/node_modules/next/dist/compiled/next-server/server.runtime.prod.js',
        '/var/task/___next_launcher.cjs'
    ],
    page: '/api/identify'
}

What I've tried

I have tried installing jimp as a dependency to the main project - didn't work. I have tried updating, uninstalling, reinstalling, and rebuilding the tfjs-image-node package - didn't work.

I am running out of ideas as to what could cause this issue.

All my code:

App:
https://github.com/kevinanielsen/seiko-identifier/

TFJS-Image-Node package:
https://github.com/kevinanielsen/tfjs-image-node/