iPhoto file importing

Just got our new imac last week, and the only problem (yet) that I am having trouble with is finding out how to import photo files from any source and have them stored on an external hard drive. I can copy the files to the external HD, and then tell iphoto where they are, and import them. But I cannot find a setting that tells iphoto to store all imported files on the extexternal HD. I have unchecked "copy items to iphoto library" in preferences, so the files stay only on the external HD. But when I choose "import to library" when importing from a CD or memory card, it places these files on the main HD in the imac, as they do not show up on the external drive. I am looking for a setting such as "location of iphoto library" where I can designate the external drive as the location for all imported files. Any ideas, guys??? Thanks

Hold down the option key when you start iPhoto. You will be prompted to "create a library", "choose a library", etc. Choose the library on your external. From then on, until you do the same thing again (Hold down the option key and select a different library), you will be importing to the external. Hope this helps.

Thanks so very much, Mary. You have made such a complex problem become so simple to solve. Very much appreciated!!!
Cam