How to remove anchor tags in image in wordpress plugin development?

Solution:

  add_filter( 'the_content', 'attachment_image_link_remove_filter' );

    function attachment_image_link_remove_filter( $content ) {

            $content =preg_replace(array('{<a(.*?)(wp-att|wp-content\/uploads)[^>]*><img}','{ wp-image-[0-9]*" /></a>}'),array('<img', '" />'),             $content);

        return $content;
    }


/*place this code in your functions.php*/


/*if you wanna remove anchor tags which has image links, follow below code*/
add_filter( 'the_content', 'attachment_image_link_remove_filter' );

function attachment_image_link_remove_filter( $content ) {
    global $post;
    $exceptional_cjtypes = array("Mashup");
    $cjtype = wp_get_post_terms($post->ID, "cjtype");
    if(!in_array(strtolower($cjtype[0]->name), array_map('strtolower', $exceptional_cjtypes))) {
        $content =preg_replace(
                array('{<a href="(.*?(gif|jpeg|jpg|png))"><img}',
                    '{ wp-image-[0-9]*" /></a>}'),
                array('<img', '" />'),
                $content
            );
    }
    return $content;
}