After re-installing my Snow Leopard I cannot gain access to my external multi-giga photo drive to import all the images back into iPhoto. They do show up as tiny thumbnails but cannot be called into the editor.
iPhoto keeps all the images in a file called "iPhoto Library". This is a separate copy of the images from the original! Assuming that iPhoto is installed on your Mac (if not, download it first), run iPhoto and import the images into it. You may want to read the thread at https://discussions.apple.com/thread/2442208 before you do this. Also, remember that as you have a large number of photos, importing them and rebuilding the library will take some time.
By the way, the library is an archive file. If you want to export images from it, simply hold shift as you double-click on the library file and it will open as an ordinary folder. Unfortunately, you can't import photos by reversing the process...
About Disk Utility's Repair Disk Permissions feature
is there any error messages?