Iphoto crashes and duplicates..

Last night I loaded about 20Gb of pictures in my iPhoto library. During the import of the last folder, iPhoto crashed. When opening it again, all the new folders created were grey and empty. So I deleted them, deleted them and emptied the trash can.

Today, I imported everything again. The result, there must be some duplicates hidding somewhere, because my iPhoto library just went from 60Gb to a 100+Gb

Any ideas what could help??