Custom permalinks with NextGen Gallery

I set wordpress default permalinks to /%category%/%postname%/. I’m using NextGen Gallery. So when i use imagebrowser instead of jQuery effect in NG Gallery, it creates custom url for every image like category/postname/?pid=no. where category,postname and no. varies. I just want to change it into image/no., where image should be a fix word. And url rewrite should work only with nextgen image, it should not affect the wordpress post urls. So help me please.

http://wordpress.org/extend/plugins/nextgen-gallery/