$file_sizes = array(
		array(100, 75),
		array(160, 120),
		array(300, 200),
		array(200, 150),
		array(620, 400),
		array(1024, 768)
	);
if($file->getWidth() / $file->getHeight() >= 1.5)
{
	foreach($file_sizes as $key => $size)
	{
		$small_file_path = '/home/rocko/Desktop/kingo-disko/test/photo-test/res1_st'.$key.'.jpg';
		$line = $file->getHeight() * $size[0] / $size[1];
		$file->crop('center', 'center', $line, $file->getHeight())->resize($size[0], $size[1])->saveToFile($small_file_path);
	}
}
else
{
	foreach($file_sizes as $key => $size)
	{
		$small_file_path = '/home/rocko/Desktop/kingo-disko/test/photo-test/res1_st'.$key.'.jpg';
		$line = $file->getWidth() * $size[1] / $size[0];
		$file->crop('center', 'center', $file->getWidth(), $line)->resize($size[0], $size[1])->saveToFile($small_file_path);
	}
}

aspect ratio friendly image resize

php, resize, image

PHP