php mysql and array function?

[Unknown]

i have 1 column in my mysql table name (mytable) like below

=======
column
=======
555
666
777
888
999
====

now i want to show this result in array like

$myarray = array("555","666","777","888","999");

how to make it possible?
question was just example,

=============
number | image
=============
555 | man.jpg
666 | man2.jpg
777 | man3.jpg
888 | man4.jpg
999 | man5.jpg
===============

$phrase = "555 is the image of 777 and 999 is best.";
$main = array("555", "666", "777", "888", "999");
$main2 = array("man.jpg", "man2.jpg", "man3.jpg", "man4.jpg", "man5.jpg");

$newphrase = str_replace($main, $main2, $phrase);