I've a theme which supports multiple templates, each with a header background image whose color can be set by the site owner via a colorpicker widget in my theme's options panel. This has the effect of opening the background image, recoloring it and resaving it back to the server.

I've had zero issues with this routine until recently when a customer installed the theme on a web host whose default read/write permissions are apparently much more restrictive than the norm. In this case, the user was unable to alter the colors of the template images because of the permissions settings.

I'm looking for a bit of understanding on what the permissions would need to be (assuming I purposefully set them via script) to allow the logged in wordpress user to write to files under my theme's styles directory.

The code I'm using to write to the image file is below...

    $img = imagecreatefromgif("../wp-content/themes/mytheme/styles/".get_option('my_theme')."/image.gif");
    $color = imagecolorallocate($img, $info["red"], $info["green"], $info["blue"]);
    imagecolorset($img, 0, $info["red"], $info["green"], $info["blue"]);
    imagegif($img, $path);