Update to match trunk as of 2003-06-17.

This matches two changes:
- Anupama made the caching tests use downstream_caching.html
(Thanks to her for help in updating this)
- Jan updated some configuration defaults, which made some images
compress more.
Merge pull request #412 from morlovich/morlovich-trunk-tracking-20030614

Update to match trunk as of 2003-06-17 (r3162)