Get MIME Type via PHP
There's no easy way. You could try:
http://www.php.net/manual/en/function.finfo-file.php
// return mime type ala mimetype extension$finfo = finfo_open(FILEINFO_MIME_TYPE);Of course, this assumes you can install PECL extensions.
I think you need head. Quickest way is to do a head request, or in PHP under apache you can use apache_lookup_uri or in PHP 5.3 you can use FileInfo (I'd still recommend apache_lookup_uri or a simple head request though).
Its never a good idea to try and find the mime type based on the file extension, as this can obviously be renamed by the used whos uploading - from .exe to .jpg
Real mime type detection is part of your overall security measures.