This module uses an image when creating watermarks. It also accepts an image to use as watermark. The library it is built on uses Exif functions. If you see a PHP fatal error about "exif_read_data" and your store cannot operate that means the Exif functions are not installed with the PHP running on your server.

The "exif_read_data" function is built-in PHP function and part of the PHP Exif Image Processing functions. You will have to ask your host to rebuilt Apache/PHP with Exif functionality included. This will solve the problem and the module will start working properly as well as your store.