add_filter('the_content', 'the_content_replace_tags', 1, 20);
function the_content_replace_tags($content){
    
    $patterns = array("#(<img.*title=\")[^\"]*(\"[^>]*>)#", "#(<img.*alt=\")[^\"]*(\"[^>]*>)#");
    $replacements = array("\\1\\2", "\\1\\2");
    
    $content = preg_replace($patterns, $replacements, $content);

    return $content;
}