Auto set permissions of uploaded media ?

goals:

1) unreadable /images/ directory so scrapers cant index the directory and waste my bandwidth

2) readable image files so the picture displays

I have removed read permissions from folder:
d-wx–x– 2 root root 4096 2010-10-08 02:30 images
and set the image readable manually:
chmod 755 smart-car-concept.png

This works great and fine, however new uploaded images arent the permissions needed and thus unreadable.

I could kick this task to the chron daemon, but

There has to be a way to set this in the WP gui