What are some common pitfalls when using the mail() function in PHP, especially when sending emails with embedded images?

When using the mail() function in PHP to send emails with embedded images, a common pitfall is not properly setting the Content-Type header to multipart/related and including the appropriate boundary. This can result in the images not being displayed correctly in the email. To solve this issue, make sure to set the Content-Type header correctly and include the boundary in the email headers. 

$to = 'recipient@example.com';
$subject = 'Example Email with Embedded Image';
$message = '<html><body>';
$message .= '<p>This is an example email with an embedded image:</p>';
$message .= '<img src="cid:unique_image_id">';
$message .= '</body></html>';

$boundary = md5(uniqid(time()));
$headers = "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: multipart/related; boundary=\"$boundary\"\r\n";
$headers .= "From: sender@example.com\r\n";
$headers .= "Reply-To: sender@example.com\r\n";

$body = "--$boundary\r\n";
$body .= "Content-Type: text/html; charset=ISO-8859-1\r\n";
$body .= "Content-Transfer-Encoding: 7bit\r\n\r\n";
$body .= $message . "\r\n";

$body .= "--$boundary\r\n";
$body .= "Content-Type: image/jpeg\r\n";
$body .= "Content-Transfer-Encoding: base64\r\n";
$body .= "Content-ID: <unique_image_id>\r\n";
$body .= "X-Attachment-Id: unique_image_id\r\n\r\n";
$body .= chunk_split(base64_encode(file_get_contents('image.jpg'))) . "\r\n";

$body .= "--$boundary--\r\n";

mail($to, $subject, $body, $headers);

Keywords

mail function embedded images MIME types email headers file paths

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