This error message in Codeigniter indicates that you are attempting to return a variable by reference, but only variable references can be returned by reference.
To decode a base64 encoded image string and save it as a JPG file in PHP, you can use the following code:
PHP_SELF, PATH_INFO, SCRIPT_NAME, and REQUEST_URI are all superglobal variables in PHP that provide information about the current URL being requested.
In CodeIgniter, you can use the redirect() function to redirect the user's browser to a new page.