I've been working on an iPhoto plugin to upload images to Scrapbook. Its currently in beta: you can download it at:
(requires Mac OS X 10.3 or later, and iPhoto 4)
It will currently upload photos at full size, or at a choice of reduced sizes. I know there are plenty of features I should be adding, but at the moment I'm keen to make sure the basic functionality is solid.
To install it, download the disc image. Make sure that iPhoto is not running. Select iPhoto in your Applications folder, select "Get Info" (from the File menu or from the contextual menu), open the Plugins section of the info dialogue and click on "Add...". In the file dialogue, navigate to the mounted disc image and choose "LiveJournal.iPhotoExporter". Close the info dialogue, and launch iPhoto.
Updates will be posted to filmgold.