I've created a website of high resolution scans of varieties on Australian stamps, the Australian Commonwealth Stamps Varieties Image Database.
The Australian Commonwealth Specialists Catalogue is the "bible" for collectors, but the images are quite poor. I hope my site can help collectors to identify varieties more readily.
SG116a with "re-entry to T and neck" (BW138e)
The site is still quite bare, but new images are being uploaded daily. If you think the site will help you, please bookmark it and pop back often. You can also subscribe to receive advice of updates.You can even make a small donation if you have a mind to!