Uploading and reading an image from s3 via postman and lambda - node.js

Question

I am trying to write a code where I am sending an image or array of images via multipart/form-data as in the below images:
Click here for the postman Screenshot
I am trying to store these images to an S3 bucket and then trigger another lambda to read the images to perform text extraction using AWS rekognition.
Code for the lambda that is storing the images is as below:
var AWS = require('aws-sdk')
var express = require('express')
var multer = require('multer')
var multerS3 = require('multer-s3')
var bodyParser = require('body-parser')
const cors = require('cors')
var app = express()
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cors())
const env = process.env.NODE_ENV || 'prod'
AWS.config.update({
accessKeyId: 'ACCESS_KEY',
secretAccessKey: 'SECRET_KEY',
region: 'ap-south-1'
});
var s3 = new AWS.S3({
region: "ap-south-1"
})
var lambda = new AWS.Lambda({
region: "ap-south-1"
});
var upload = multer({
storage: multerS3({
s3: s3,
bucket: 'MY_BUCKET_NAME',
metadata: function (req, file, cb) {
cb(null, { fieldName: file.fieldname });
},
key: function (req, file, cb) {
req.originalname = file.originalname
cb(null, req.originalname)
}
})
})
app.post('/', upload.array('file', 2), function (req, res, next) {
const params = {
FunctionName: "ANOTHER_LAMBDA_NAME",
Payload: JSON.stringify({ "fileName": req.originalname })
};
return lambda.invoke(params, (err, data) => {
if (err) console.log("err", err.stack);
else {
res.json(data.Payload)
}
});
})
if (env === "dev") {
const port = process.env.port || 4000
app.listen(port, () => console.log(`server is running on ${port}`))
}
else {
module.exports = app
}
Code for another lambda is as below:
var AWS = require('aws-sdk')
var s3 = new AWS.S3()
const rekognition = new AWS.Rekognition()
exports.handler = function(event, context) {
var params = {
Image: {
S3Object: {
Bucket: 'MY_BUCKET_NAME',
Name: event.filename,
}
}
};
rekognition.detectText(params, function(err, data) {
if (err) console.log(err, err.stack);
else context.succeed(data); // returns "null"
});
};
After this, I created an API Gateway which triggers the first lambda to upload the files in s3 as in the picture above. The response I get is "null"
The main problem seems to be that the image is getting stored in S3 Bucket. But when I download that image and try to open it, it gives the following error:
The file “EPICared.jpg” could not be opened. It may be damaged or use a file format that Preview doesn’t recognize.
So what do you guys suggest I should be doing? Where am I going wrong? I cannot figure out why the image cannot be opened or read by the other lambda.