PHP+Image type detection - php

Question

I have a email script that sends file trough attachment from server. The email is sent using phpmailer and the attached file is attached in code like this:
$_img = (object) ($img);
if (!empty($_img->src)) {
$ext = substr($_img->src, -3);
$imginfo_array = getimagesize($_img->src);
$mime_type = $imginfo_array['mime'];
switch($mime_type) {
case "image/jpeg":
$type = "image/jpeg";
break;
case "image/png":
$type = "image/png";
break;
case "image/gif":
$type = "image/gif";
break;
}
$string = file_get_contents($_img->src);
$mail->AddStringAttachment($string, $i . '.' . $ext, 'base64', $type);
}
The problem occurs when a image is not properly saved before adding it to server. If one user decides that the file 'test.jpg' shoul be 'test.png' the attached file will not be visible via email.
The $_img->src is a file saved on server.
I am trying to check for mime type but still with no success.
I want to be able to tell the script that the correct file type is the one auto detected not determined by the extension.
Could someone give me a clue about how this could be done?

Answer 1

$_img = (object) ($img);
if (!empty($_img->src)) {
//$ext = substr($_img->src, -3);
// better solution for get file extension (with variable length: "jpeg" or "jpeg")
$ext = pathinfo($_img->src, PATHINFO_EXTENSION);
$imginfo_array = getimagesize($_img->src);
$mime_type = $imginfo_array['mime'];
switch($mime_type) {
case "image/jpeg":
$type = "image/jpeg";
$ext = 'jpg';
break;
case "image/png":
$type = "image/png";
$ext = 'png';
break;
case "image/gif":
$type = "image/gif";
$ext = 'gif';
break;
// fix for others mime type
default:
$type = "application/octet-stream";
}
// for binary file use AddAttachment()
//$string = file_get_contents($_img->src);
//$mail->AddStringAttachment($string, $i . '.' . $ext, 'base64', $type);
// I hope that the variable $i is set from previous code
$mail->AddAttachment($_img->src, $i . '.' . $ext, 'base64', $type)
}

Answer 2

You can detect the type of the image with the IMAGETYPE_XXX constants at index 2 of the returned imginfo_array. The returned mime field you are using is much less reliable.
See documentation:
http://php.net/manual/en/function.getimagesize.php
Type contants:
http://php.net/manual/en/image.constants.php