WP Idea Stream Custom : Replace the author avatar by the first image found in the idea content

wp-idea-stream-custom.php

<?php
// Exit if accessed directly
if ( ! defined( 'ABSPATH' ) ) exit;

/**
 * Replace the author avatar by the first image found in the idea content
 * if no image was found keep the avatar.
 */ 
function first_idea_image_as_avatar( $avatar_link, $author, $avatar, $idea ) {
	if ( empty( $idea->post_content ) ) {
		return $avatar_link;
	}

	preg_match_all( '/\<img.+src\=(?:\"|\')(.+?)(?:\"|\')(?:.+?)\>/', $idea->post_content, $matches );
	
	if ( empty( $matches[1][0] ) ) {
		return $avatar_link;
		return $matches[1][0];
	}

	$image = '<img src="' . esc_attr( $matches[1][0] ) . '" class="thumbnail thumbnail-96" height="96px" width="96px" />';
	
	return '<a href="' . esc_url( wp_idea_stream_ideas_get_idea_permalink( $idea ) ) . '" title="' . esc_attr( $idea->post_title ) . '">' . $image . '</a>';
}
add_filter( 'wp_idea_stream_ideas_get_author_avatar', 'first_idea_image_as_avatar', 10, 4 );