cakephp 2.4 upload an image - cakephp

Question

i'm trying to upload an image and make a thumbnail of this image by using this Behavior (github) tutorial
I'm using the blog tutorial on cakephp website.
I'm getting this following errors each time I want to upload the images. I'm dowloading an .jpeg file
Invalid file type. Only .jpg, .jpeg, .png, .gif allowed.
My Model/Post.php
<?php
class Post extends AppModel {
public $validate = array(
'title' => array(
'rule' => 'notEmpty'
),
'body' => array(
'rule' => 'notEmpty'
)
);
public $actsAs = array('ImageUpload' => array(
'image' => array(
'required' => false,
'directory' => 'img/uploads/',
'allowed_mime' => array('image/jpeg', 'image/pjpeg', 'image/gif', 'image/png'),
'allowed_extension' => array('.jpg', '.jpeg', '.png', '.gif'),
'allowed_size' => 2097152,
'random_filename' => true,
'resize' => array(
'thumb' => array(
'directory' => 'img/uploads/thumbs/',
'phpThumb' => array(
'far' => 1,
'bg' => 'FFFFFF',
'zc' => 0
),
'width' => 230,
'height' => 150
),
'max' => array(
'directory' => 'img/uploads/thumbs/',
'phpThumb' => array(
//'far' => 1,
//'bg' => 'FFFFFF',
'zc' => 0
),
'width' => 400,
'height' => 300
)
)
)
)
);
}