Twig/CropTwigExtension.php
public function getSize($image, $relative = false)
    {
        if (!$image instanceof File) {
            if ($relative) {
                $image = $this->root_path . $image;
            }

            $image = new File($image);
        }

        return getimagesize($image->getRealPath());
    }
public function getSize($image, $relative = false)
    {
        if (!$image instanceof File) {
            if ($relative) {
                $image = $this->root_path . $image;
            }

            $image = new File($image);
        }

        return getimagesize($image->getRealPath());
    }
Returns image size info

@param $image
@param bool $relative
@return array