Creating an album on Facebook... Privacy settings?

[Tickle Mouse]

Can you tell me more about the privacy settings when creating an album on Facebook...

I know silly question BUT what exactly is 'friends of friends' compared to 'only friends'?

I only ask because if I choose 'friends of friends' does that mean if the album shows up in a friends highlight bar then.... friends who are not my friends can see the whole album?

Often when I look at a comment my friend has made on anothers album I can see the whole thing... Is it because this option is selected?

Can it still be made visible when selecting 'only friends'?

Sorry I know this is confusing................