Available memory issue

my old G4 desktop is running 10.4.11. i recently had to do an erase and install due to various reasons. after reloading my iPhoto library i was told that my disk was almost full. i should note that i was expecting to have at least 16 gigs of free space when all was done because that's where i was at before my erase and reinstall procedure. it's an 80 gig factory HD BTW. upon double clicking on my HD, oddly, it says i still have 73 gigs of space left- which makes no sense given the amount of photos and videos that were just reloaded. but then when i click on to my Pictures folder i'm told i've only have 140 MB. what gives?

 

tried that. here's what i got:

the HD says the capacity is 76.69 GB, and that there's 73.83 GB available.

yet, my Pictures folder which holds all the iPhoto lists its size as 41.43 GB

basic math tells us that this is all wrong and makes no sense. this is the last thing i'd expect from a newly reformatted system.