<?php
#!/usr/bin/php
#
# enhanceLSB.php
#
# Utility to 'enhance' the LSB in a Windows BMP file
#
$bmpHeaderLength = 200;
$byteCounter = 0;
$bmpHandle = fopen ("file2.bmp", "r");
$outputHandle = fopen ("output.bmp", "a");
while ($byte = fgetc($bmpHandle) {
    if ($byteCounter > $bmpHeaderLength) {
        // if LSB = 1 then set entire byte to 1
        if ($byte & 1) {
            $byte = 1;
        }
    }
    $byteCounter++;
    fwrite ($outputHandle, $byte);
}
fclose ($bmpHandle);
fclose ($outputHandle);
?>