As a matter of fact, I’m not sure if there is some buggyness or just a bit confusing code going on.
In includes/shortcodes.php
l 84. there’s this check:
<div class="woo-login-popup-sc-bg" <?php echo ( is_array( $options ) && isset( $options['background'] ) && !empty( $options['background'] ) ) ? 'style="background-image:url(\''. $options['background'] .'\')"' : ''; ?> ></div>
When I check the option saved the ‘background’ property is empty, yet there is the default image from the CSS which gets output instead:
background: transparent url("../images/default-bg.jpg") center center;
Maybe this should be documented better, i.e. instructing themes to overwrite the background image to none to get rid of the image.
Why not simply set the default image as the default option value, so removing the image would also remove the default? The plugin admin planel could then have a option to “use default image”.