test_upload_detailed.php

<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $target_dir = "uploads/";
    $target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
    $uploadOk = 1;
    $imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));

    // Check if image file is a actual image or fake image
    if(isset($_POST["submit"])) {
        $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
        if($check !== false) {
            echo "File is an image - " . $check["mime"] . ".<br>";
            $uploadOk = 1;
        } else {
            echo "File is not an image.<br>";
            $uploadOk = 0;
        }
    }

    // Check if file already exists
    if (file_exists($target_file)) {
        echo "Sorry, file already exists.<br>";
        $uploadOk = 0;
    }

    // Check file size
    if ($_FILES["fileToUpload"]["size"] > 500000) {
        echo "Sorry, your file is too large.<br>";
        $uploadOk = 0;
    }

    // Allow certain file formats
    if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
    && $imageFileType != "gif" ) {
        echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.<br>";
        $uploadOk = 0;
    }

    // Check if $uploadOk is set to 0 by an error
    if ($uploadOk == 0) {
        echo "Sorry, your file was not uploaded.<br>";
    // if everything is ok, try to upload file
    } else {
        if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
            echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.<br>";
        } else {
            echo "Sorry, there was an error uploading your file.<br>";
            echo "Error details: " . error_get_last()['message'] . "<br>";
        }
    }
    
    echo "Upload directory: " . realpath($target_dir) . "<br>";
    echo "Target file: " . $target_file . "<br>";
    echo "Temporary file: " . $_FILES["fileToUpload"]["tmp_name"] . "<br>";
    echo "Current working directory: " . getcwd() . "<br>";
}
?>
<form action="test_upload_detailed.php" method="post" enctype="multipart/form-data">
    Select image to upload:
    <input type="file" name="fileToUpload" id="fileToUpload">
    <input type="submit" value="Upload Image" name="submit">
</form>