Difference among Sort, SORT_NATURAL, SORT_FLAG_CASE

asort($array1,SORT_NATURAL) == natsort($array1) == uasort($array1, "strnatcmp");

asort($array1,SORT_NATURAL | SORT_FLAG_CASE) == natcasesort($array1) == uasort($array1, "strnatcasecmp");

$array1 = array("img12.png", "img10.png", "img2.png", "img1.png");

sort($array1);
echo "Standard sorting\n";
print_r($array1);

sort($array1,SORT_NATURAL);
echo "\nNatural order sorting\n";
print_r($array1);

$array1 = array("img12.png", "img10.png", "Img2.png", "img1.png");

sort($array1);
echo "Standard sorting\n";
print_r($array1);

sort($array1,SORT_NATURAL); // like natsort, but index not preserved.
echo "\nNatural order sorting\n";
print_r($array1);

sort($array1,SORT_NATURAL | SORT_FLAG_CASE); like natcasesort, but index not preserved.
echo "\nNatural order sorting, case insensitive\n";
print_r($array1);