If images are displayed as a PINK square. Changing the get parameter _embed=1 to _embed=0 makes it work I changed program/lib/Roundcube/rcube_message.php (line 158) return $this→optget_url? . '&_part=' . $mime_id . ($embed ? '&_embed=1&_mimeclass=' . $embed : );

to have _embed=0