Developer James Sentman has released Image in a Hurry, an image browser and export utility for iPhoto. It lets you browse thumbnails and choose images for exporting, resizing, and re-compressing.
Image in a Hurry requires Mac OS 10.2 (“Jaguar”) or greater and iPhoto 2.0. In the current version, there’s no way to select an iPhoto library in other than the default location.
Image in a Hurry costs US$12. You can download a demo version that’s not limited in any way. However, it will remind you occasionally to register.