In  winhttrack  setting "Browser ID - Browser "Identity" "as 

Mozilla/4.0 (compatible; MSIE 6.0; Windows 98; Win 9x 4.90)

,this is ie6's identity.
and add Scan Rules:
+http://www.puregraffiti.com/forum/upload/attachment.php?s=*
to catch attachment pictures.
and rename downloaded attachment*.html to attachment*.jpg .