Few days ago I worked on a project. Client was wanting extra two new types (review & question) at comment form. All things implemented successfully. Only problem was that avatar for review/comment type was not coming at frontend & backend. I researched too much and got that avatar is allowed for comment type only.
But you can enable it without modify the WordPress files. There have a filter “get_avatar_comment_types” and you can alter the default settings. I just applied following PHP code and added into my theme’s functions.php file. It was working like a charm.
* Enable the avatar for different comment types
* @package CoreFunctionality
* @author Paul Chinmoy
* @since 1.0.0
* @license GPL-2.0+
add_filter( 'get_avatar_comment_types', 'paul_enable_avatar_comment_types' );
* @param array $types An array of content types. Default only contains 'comment'.
function paul_enable_avatar_comment_types( $types )
//* here 'review', 'question' are my custom comment types
return array( 'comment', 'review', 'question' );