problem downloading photos from one album from iphoto

I am using iphoto '09, version 8.1.2. I uploaded 250 photos from my camera. Then I created an album in iphoto with 100 photos. I then tried to export the the photos in the album with the 100 pics to one folder on my desktop. But iphoto exported all 250 original photos to the desktop folder. I tried it several times using the Smart Album too. I have done this many times in the past and never had this problem before. Please advise what I am doing wrong so I can export just 100 photos from one album. Thanks.

Did you select the 100 photos first?