7000 pictures missing on Iphoto. Help Please

Hello All

I am using Iphoto 9.5.1 with Mavericks 10.9.4. I used to have 8500 pictures on Iphoto. 2 weeks ago I am sure they were all on Iphoto. My library was about 56gb.

Last weekend when I opened Iphoto, 7000 pictures were missing. All events, albums etc was there, but the pictures were missing.

I went to check my library - when I clicked on Iphoto library files, it showed 56gb file and 2 seconds latter changed to 14gb. I looked inside the package content and couldn't find a lot of pictures inside Master folder.

Last weekend I replaced my Imac HD and restored everything from Time Machine. First I tough it was a problem with Time Machine. Got my old HD and checked my iphoto library. When I clicked on the file it went from 56gb to 14gb again. Opened package content to check Master Folder and the pictures weren't there.

In the mean time I formatted Time Machine HD with my old backups. i am trying to restore and see if I can get the pictures back and I am also working on my old HD to see if I find any deleted pictures on it, but I am sure it will take some time.

Any idea what happened to my pictures and what I can do to solve it.

It's pretty weird because not all pictures where gone.

Any help will be appreciated