An allowed_types and Upload issue

[eluser]Riente[/eluser]
Hello everyone, I have a problem.

I indicate two allowed file types $config[‘allowed_types’] = ‘gif|jpg’;
The point is only the first one works fine. I mean that I can upload gif-files successfully, and when trying to upload a jpg-file I get an error “The filetype you are attempting to upload is not allowed”.
If I write $config[‘allowed_types’] = ‘jpg|gif’; (i.e. swap their positions) then I upload jpg-files just fine, but have problems uploading gif-files.

Here’s my code:

Code:

$this->load->library('upload');
$config['upload_path'] = './img/logos/brands/';
$config['allowed_types'] = 'gif|jpg';
$config['max_size'] = '8192';
$config['encrypt_name'] = TRUE;
$config['max_width']  = '0';
$config['max_height']  = '0';
$this->upload->initialize($config);

if (!$this->upload->do_upload("file"))
{
$img = $data['item']['img'];
}
else
{
// ...
}

What can be the problem?