What security measures should be taken into consideration when allowing users to upload images and display HTML code on a website using PHP?

When allowing users to upload images and display HTML code on a website using PHP, it is crucial to implement security measures to prevent potential security vulnerabilities such as cross-site scripting (XSS) attacks and file upload vulnerabilities. One way to enhance security is by validating and sanitizing user inputs before processing them. Additionally, restricting file types, setting proper file permissions, and storing uploaded files in a secure location are also important considerations. 

// Validate and sanitize user inputs
$uploadedImage = $_FILES['image']['tmp_name'];
$allowedTypes = ['image/jpeg', 'image/png'];
if (!in_array($_FILES['image']['type'], $allowedTypes)) {
    die('Invalid file type. Only JPEG and PNG files are allowed.');
}

// Move the uploaded image to a secure location
$uploadPath = 'uploads/';
$newFileName = uniqid() . '_' . $_FILES['image']['name'];
if (!move_uploaded_file($uploadedImage, $uploadPath . $newFileName)) {
    die('Failed to upload image.');
}

// Display the uploaded image
echo '<img src="' . $uploadPath . $newFileName . '" alt="Uploaded Image">';

Keywords

File upload image validation HTML filtering cross-site scripting secure coding.

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