public function decreaseSide($side, $size) {
		$x = $y = 1;
		$x2 = $this->width;
		$y2 = $this->height;
		switch ($side) {
			case 'top':
				$y = $size;
				break;
			case 'right':
				$x2 -= $size;
				break;
			case 'bottom':
				$y2 -= $size;
				break;
			case 'left':
				$x = $size;
				break;
		}
		$this->crop($x, $y, $x2, $y2);
		return $this;
	}