I cannot upload .JPG file, but can upload .jpg file in PHP

Question

This is my code. I can perfectly upload .jpg file. But images with .JPG file extensions are not getting uploaded. No error is shown. Here is my code

$nameofimage = mt_rand(0, 1000000) .basename($_FILES["fileToUpload"]["name"]);
$target_dir = "uploads/";
$target_file = $target_dir . $nameofimage;
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
echo $imageFileType;

// 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"] . ".";
        $uploadOk = 1;
    } else {
        echo "File is not an image.";
        $uploadOk = 0;
    }
}
// Check if file already exists
if (file_exists($target_file)) {
    echo "Sorry, file already exists.";
    $uploadOk = 0;
}
// Check file size
if ($_FILES["fileToUpload"]["size"] > 1000000) {
    echo "Sorry, your file is too large. Please keep it under 1 MB";
    $uploadOk = 0;
}
// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" && $imageFileType != "JPG" ) {
    echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
    $uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {

    } else {
        echo "Sorry, there was an error uploading your file.";
        if (is_dir($target_file) && is_writable($target_file)) {
        // do upload logic here
        } else {
            echo ' Upload directory is not writable, or does not exist.';
        }
    }
}

Here, the if condition is also false. I don't know what's going, please help, i am stuck at this from 2 days.

if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" && $imageFileType != "JPG" ) {
    echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
    $uploadOk = 0;
}

Answer 1

just convert image name in lowercase..

$nameofimage = mt_rand(0, 1000000) .basename($_FILES["fileToUpload"]["name"]);

$nameofimage = strtolower($nameofimage);