Use addFrame to pass the image directly?

I have done a small change to the code to simplify its usage by passing the frame data direct into addFrame, I understand that it may be mixing different levels of classes (FileImageCanvas is now required inside GifBuilder) and your code is well structured but as I'm not an OO programmer I don't see any bad in it ;-)

Now I can either:

$builder->addFrame(__DIR__ . '/horse/' . $i . '.png')

Or:

$builder->addFrame(new FileImageCanvas(__DIR__ . '/horse/' . $i . '.png'))

This is just an idea and since I made the change in my downloaded version I'm sharing the change.

I don't know how to format code here so I also added the change here to make it easier to see:
pastebin.com/AtDpEVfG

Unformatted version here:
public function addFrame($data = null)
{
$frame = new Frame();

if (gettype($data) == 'object' && get_class($data) == 'movemegif\domain\FileImageCanvas')
$frame->setCanvas($data);
else if (is_string($data) && file_exists($data))
$frame->setCanvas(new FileImageCanvas($data));
else if ($data != null)
throw new MovemegifException('Unknown datatype. Use either a path or a Canvas object.');

$this->extensions[] = $frame;
return $frame;
}

Why not create separate functions for these variants (i.e. addFileFrame($path))? That way you don't have to mix types in your function arguments.

You are right, since the code is static there shouldn't be a need for the function to guess the file type and it would make it more organized. Thanks.