account/update_profile_image stack trace "Incorrect signature"

[amboy00]

Is anyone else getting a stack trace when updating the profile Image?

$avatar_response = $this->tweet->call('post', 'account/update_profile_image', array('@image' => '@{$loc}'));

I've tried other combinations, no at sign, /1 in the url, same problem. The only thing I learned was that in this call, the image needs to be a raw multi-part file. Is that something this library supports?

Thanks