Upload Image PHP - error in verifying ISSET - php

Question

I followed this link to upload image from android to server. But the upload is failed on PHP part, so I added some echo to keep track on which one triggered the error. And I found that even though I already set an image to upload (I use Postman), the error of 'Please choose a file' is triggered.
<?php
//importing dbDetails file
require_once('dbDetails.php');
//this is our upload folder
$upload_path = 'uploads/';
//Getting the server ip
$server_ip = gethostbyname(gethostname());
//creating the upload url
$upload_url = 'http://xxx/xxx/'.$upload_path;
//response array
$response = array();
if($_SERVER['REQUEST_METHOD']=='POST'){
echo "method OK";
//checking the required parameters from the request
if(isset($_POST['name']) && isset($_FILES['image']['name'])){
echo "isset ok";
//connecting to the database
$con = mysqli_connect(HOST,USER,PASS,DB) or die('Unable to Connect...');
//getting name from the request
$name = $_POST['name'];
//getting file info from the request
$fileinfo = pathinfo($_FILES['image']['name']);
//getting the file extension
$extension = $fileinfo['extension'];
//file url to store in the database
$file_url = $upload_url . getFileName() . '.' . $extension;
//file path to upload in the server
$file_path = $upload_path . getFileName() . '.'. $extension;
//trying to save the file in the directory
try{
//saving the file
move_uploaded_file($_FILES['image']['tmp_name'],$file_path);
$sql = "INSERT INTO uploads (id, fileUpload, name) VALUES (NULL, '$file_url', '$name');";
//adding the path and name to database
if(mysqli_query($con,$sql)){
//filling response array with values
$response['error'] = false;
$response['url'] = $file_url;
$response['name'] = $name;
}
//if some error occurred
}catch(Exception $e){
$response['error']=true;
$response['message']=$e->getMessage();
}
//displaying the response
echo json_encode($response);
//closing the connection
mysqli_close($con);
} else{
echo "isset error";
$response['error']=true;
$response['message']='Please choose a file';
}
}
function getFileName(){
$con = mysqli_connect(HOST,USER,PASS,DB) or die('Unable to Connect...');
$sql = "SELECT max(id) as id FROM uploads";
$result = mysqli_fetch_array(mysqli_query($con,$sql));
mysqli_close($con);
if($result['id']==null)
return 1;
else
return ++$result['id'];
}
?>
Screenshot from Postman
Please guide me what did I missed?