php getimagesize function gets image size

/* 1.jpg The image whose size is to be obtained*/
$arr = getimagesize("1.jpg");
/**
 * Here $arr is an array type
 * $arr[0] is the width of the image
 * $arr[1] is the height of the image
 * $arr[2] is the format of the image, including jpg, gif, png, etc.
 * $arr[3] is the width and height of the image, and the content is width="xxx" height="yyy"
*/
/* The following output Same content*/
echo "";
echo "";
?>