Da, se poate face ce vrei tu:
Cod PHP:
$userAgent = $_SERVER['HTTP_USER_AGENT'];
if(stristr(strtolower($userAgent), 'googlebot') === FALSE) {
//NORMAL USER BROWSING SHOW CONTENT
}
else {
//THIS IS GOOGLE BOT DO NOT SHOW CONTENT
}
Ar mai fi si solutia sa transformi textul in imagine folosind libraria GD din PHP 
Uite un exemplu:
Cod PHP:
<?php
// show the correct header for the image type
header("Content-type: image/jpg");
// an email address in a string
$string = "email@example.com";
// some variables to set
$font = 4;
$width = ImageFontWidth($font) * strlen($string);
$height = ImageFontHeight($font);
// lets begin by creating an image
$im = @imagecreatetruecolor ($width,$height);
//white background
$background_color = imagecolorallocate ($im, 255, 255, 255);
//black text
$text_color = imagecolorallocate ($im, 0, 0, 0);
// put it all together
imagestring ($im, $font, 0, 0, $string, $text_color);
// and display
imagejpeg ($im);
?>