Recoverable fatal error: Object of class mysqli could not be converted to string in C:\xampp\htdocs\CRUD 4\UPLOAD\upload\upcode.php on line 46


I write code but when excute code I'm find Error : Recoverable fatal error Object of class mysqli could not be converted to string 


$insertquery="insert into tbl_user(username,image)values('{$username}','{$file_name}')"; 
$iquery=mysqli_query($con,$insertquery) or die($con);
print_r($iquery);
exit;



<?php
include '../dbconnect.php';
if($_SERVER['REQUEST_METHOD']=='POST'){
    if(isset($_POST['submit']) and !empty($_POST['submit'])){

        $username=isset($_POST['username'])?$_POST['username']:NULL;
        
        if(is_null($username) or empty($username)){
            header("location:{$_REQUEST['/']}?action=username&msg=blank-username");
            exit;
        }

    

        $file=$_FILES['file'];
        $file_name = $file['name'];
        $file_type = $file['type'];
        $file_tmp_name = $file['tmp_name'];
        $file_error = $file['error'];
        $file_size = $file['size'];
        
        $fs = $file_size/1024;

        $arr = ['jpg','png','jpeg'];
        $fi= explode(".",$file_name);
        $last = end($fi);
        
        if(in_array($last,$arr))
        {
          
            if($fs<=500)
            {
                if($file_error==0)
                {
                 
                    $file_path = __DIR__."/vv/";

                    $upload_files = $file_path.$file_name;
                  
                  if( move_uploaded_file($file_tmp_name,$upload_files))
                  {
                    
                    $insertquery="insert into tbl_user(username,image)values('{$username}','{$file_name}')"; 
                    $iquery=mysqli_query($con,$insertquery) or die($con);


                    //print_r($iquery);
                    //exit;
                    
                    if($iquery){
            
                        ?>
                        <script>
                        window.alert("File Uploaded successfully");
                      
                        </script>
            
                        <?php
            
                    }else{
                        ?>
                            <script>
                            window.alert("Uploading failed");
                            // window.location.href="register.php";
                            </script>
            
                        <?php
                    }
                  }else{
                    echo "No File Movienig";
                  }
                }else{
    
                    echo "File Uploading Error";
                }

            }else{

                echo "File Size Should be bellow 500kb";
            }

        }else{
            echo "<br> InValid image";
        }

             
    }else{
        header("location:{$_REQUEST['/']}");
    }

}else{
    header("location:register.php");
}



Solutions : 

First Check Your Databse Connection

Connection Error : If you try  this :  mysqli_select_db($con,'image_db');

<?php
$con =mysqli_connect('localhost:3308','root','');
    mysqli_select_db($con,'image_db');

?>


<?php

$con =mysqli_connect('localhost:3308','root','','imgae_db');
    if($con){
        echo "No Coonection";
    }else{
        echo "Coonection Succesfully";
    }

?>

or

<?php

$con =mysqli_connect('localhost:3308','root','','imgae_db');
  

?>