The image_url parameter of the AJAX call to the editimage_bwg action of admin-ajax.php is vulnerable to reflected Cross Site Scripting. The value of the image_url parameter is embedded within an existing JavaScript within the response allowing arbitrary JavaScript to be inserted and executed. The attacker must target a an authenticated user with permissions to access this component to exploit this issue.
https://wordpress.org/plugins/photo-gallery/#developers
https://appcheck-ng.com/xss-vulnerabilities-discovered-10web-photogallery-wordpress-plugin/