Are you still as much of a wimp as you used to be? Remember the time I had you touch the spark plug on my go-cart when I was starting it up? I still laugh about the expression on your face when you got shocked, and how your hair stood on end. Dang, that was funny!
Anyway, Auntie's out for a while again today. Don't tell the other relatives, but she is taking just about everything she got for Christmas back to the stores and getting cash. I think she's going to buy a bunch of Xserves before they disappear forever to fill out that data center in the basement.
Dude, you can definitely move the iPhoto library to a bigger drive. What I'd do is look into a pair of big drives, so you'll always have a backup of that iPhoto library -- it would suck to have a pile of photos from that DSLR sitting on a mongo drive, only to have the drive take a dirt nap.
Your iPhoto library is in your ~/Pictures folder (that's a fancy way of saying bring up a Finder window, click on your Home directory -- the one that looks like a house -- and then look for the Pictures folder). To move the library, make sure that iPhoto isn't running, and then drag and drop it onto the other drive. If you have as many photos as you say you have, this may take a while.
Next, hold down the Option key and click on the iPhoto icon in the Dock to launch iPhoto. Instead of seeing iPhoto, you're going to see something like this:
Whatever is marked "default" is the library that you've been using up to this point. What you need to do is to click on one of the other libraries, make sure that the path (that's the stuff below the list of libraries) points to the copy you made on your big-a** drive, and then click that Choose button. If your library copy isn't shown, use that "Other Library" button to find it and connect to it.
You're right about higher-resolution photos taking up a lot of room. Those photos I took of your girlfriend? I had to buy some more drives for my Drobo just to keep 'em safe for future blackmail purposes.
Cheers, buddy, and Happy freakin' New Year,
Your Cousin Vinnie