Use **addslashes** in PHP.

As described in [this page][1] (in chinese), this would work:

    $main_car_pic = addslashes(get_field('car_photo'));
    $reg_ext = "#.jpg#i";
    $thumb_ext = "-150x150.jpg";
    $car_thumb = preg_replace($reg_ext, $thumb_ext, $main_car_pic);
    
    echo $car_thumb

Or simply like this:

    <?php echo addslashes(get_field('field_name')); ?>


  [1]: http://blog.linz.im/2012/acf-image-url.html