FileHandler.php

<?php
class FileHandler {
	/**
	* allowable default file types
	*/
	public $enabled_mimes = array (
			'image/png',
			'image,jpg', #and what ever you want.
		);

	/**
	* File address
	*/
	public $file;

	public function __construct($mimes=false,$file)
	{

		if (is_array($mimes)){
			//replace if defined
			$this->enabled_mimes = $mimes;
		}

		//set file address
		/****** USE real_path() or getcwd() FOR ADDRESSING *******/
		$this->file = $file;
	}

	private function setError($error_message)
	{
		//put error in session to use PRG pattern
		//you should unset it after it is first views (flash session)
		$_SESSION['file_type_error'] = $error_message;

	}

	/**
	* @return boolean
	*/
	public function processCheck($withError = "File type is not allowed")
	{
		$FileInfo = new \finfo;
		$mime = $FileInfo->file($this->file,FILEINFO_MIME);

		if (!in_array($mime, $this->enabled_mimes)){
			//set a flash error message to session or cookie to display to user
			$this->setError($withError);
			return false;
		}

		return true;

	}

}

usage :

$type = new FileHandler(false,'my/path/image.jpg');
if ($type->processCheck()){
   #success
}