To move to another machine:
To move an iPhoto Library to a new machine:
Link the two Macs together: there are several ways to do this: Wireless Network,Firewire Target Disk Mode, Ethernet, or even just copy the Library to an external HD and then on to the new machine...
But however you do choose to link the two machines...
Simply copy the iPhoto Library from the Pictures Folder on the old Machine to the Pictures Folder on the new Machine.
Then launch iPhoto. That's it.
This moves photos, events, albums, books, keywords, slideshows and everything else.
To move to an external disk:
Make sure the drive is formatted Mac OS Extended (Journaled)
1. Quit iPhoto
2. Copy the iPhoto Library from your Pictures Folder to the External Disk.
3. Hold down the option (or alt) key while launching iPhoto. From the resulting menu select 'Choose Library' and navigate to the new location. From that point on this will be the default location of your library.
4. Test the library and when you're sure all is well, trash the one on your internal HD to free up space.
In reference to the original question/answer, could I please check...
If I copy and paste my pictures folder (which includes on file called iPhoto library) onto my external hard-drive, does this mean that all of my photos are then saved on my hard-drive? And the photos will be accessible to save a few individually back onto my Mac if needed in the future?
I have done a separate Time Machine back up, but I think I understand from other discussions that that is a full library back up and not a way to access individual photos if necessary.
I was able to successfully copy photos from my MacBook Pro to my iMac. However, I had assigned locations to the photos on my MacBook Pro. When those photos were copied to my iMac, the photos don't have the location information anymore. How can I transfer that location information?
Don't copy and paste. Just drag the iPhoto Library package from your Pictures folder to the external HD. When the copying is completed launch iPhoto with the Option key held down and select the library on the EHD to open to make sure it copied over successfully and is operating correctly.
When you've determined that the EHD library is OK, relaunch iPhoto as you did previously and select the boot drive library. There you can delete those photos you don't need in the library to reduce it size. Note: iPhoto is a little finicky when it comes to deleting large numbers of photos at one time so limit the deletions to about 100-200 at a time.
You can transfer albums or Events between libraries while keeping keywords, titles, locations, descriptions, edited versions, etc. intact with the paid version of iPhoto Library Manager