iPhoto size vs. items

Hi,

I am a newbie on mac.

I transferred my windows picture database from my external HDD in my Finders "Pictures" folder. then it somehow imported the pictures in iPhoto - somehow, because, the size of Pictures folder is about 650GB and iPhoto about 350GB (see attachment). But in iPhoto, the somehow imported pictures are not visible - only 3600 items are in iPhoto - see attachment two.

Please help. Thanks in advance and cheers,

Jonas---------------------------------------------------------