Apple released, via software update, an updated to iWeb. The new version is 2.02.
About iWeb 2.0.2
This update to iWeb addresses issues with upgrading iWeb 1.x websites, and fixes some common publishing problems, and supports general compatibility issues.Note
In order to install this update you will need to download the iLife Support 8.1 update first. The iLife update supports system software components used by all iLife application, improves overall stability, addresses a number of other minor issues and supports general compatibility issues.
And yes, it fixes the “On the Web Darkly problem.” Images previewed in iPhoto survive posting via iWeb on .mac.