Photo uploader, kohana, how to implement so that the extension does not change when uploading ??

Question

Kohana

Hello, when uploading a photo, if the picture is of a different type of extension like .png .gif, etc., the photo uploader processes the photo and makes it in
.jpg does.
Loader

public function _uplakcii_img($file, $ext = NULL, $directory = NULL)
    {

        if ($directory == NULL) {
            $directory = 'media/uploads/akcii/';
        }

        if ($ext == NULL) {
            $ext = 'jpg';
        }

        $symbols = '0123456789abcdefghijklmnopqrstuvwxyz';

        $filename = '';
        for ($i = 0; $i < 10; $i++) {
            $filename .= rand(1, strlen($symbols));
        }

        $im = Image::factory($file);
        if ($im->width < 50 OR $im->height < 50) {
            return false;
        } else {
            $im->save("$directory/$filename.$ext");
            return "$filename.$ext";
        }
    }

Answer 1

The file extension can be obtained through
already in the function itself or already feed it to the input.