Craft\Imager_ImagePathsModel::__construct PHP Method

    public function __construct($image)
    {
        $this->isRemote = false;
        if (is_string($image)) {
            if (strpos($image, craft()->imager->getSetting('imagerUrl')) !== false) {
                // url to a file that is in the imager library
                $this->getPathsForLocalImagerFile($image);
            } else {
                if (strpos($image, 'http') === 0 || strpos($image, 'https') === 0 || strpos($image, '//') === 0) {
                    // external file
                    $this->isRemote = true;
                    if (strrpos($image, '//') === 0) {
                        $image = 'https:' . $image;
                    }
                    $this->_getPathsForUrl($image);
                } else {
                    // relative path, assume that it's relative to document root
                    $this->_getPathsForLocaleFile($image);
                }
            }
        } else {
            // It's some kind of model
            if (get_class($image) == 'Craft\\Imager_ImageModel') {
                $this->getPathsForLocalImagerFile($image->url);
            } else {
                if ($image instanceof \Craft\AssetFileModel) {
                    if (!$image->getSource()->getSourceType()->isSourceLocal()) {
                        // it's a cloud source, pretend this is an external file for performance
                        $this->isRemote = true;
                        $this->_getPathsForUrl($image->getUrl());
                    } else {
                        // it's a local source
                        $this->_getPathsForLocalAsset($image);
                    }
                } else {
                    throw new Exception(Craft::t('An unknown image object was used.'));
                }
            }
        }
    }