Photos with Exclamation Point...gone for good?

I have a situation where I am not able to retrieve 100 pictures from IPhoto. I can see the thumbnails but then get the exclamation point. I read and tried the suggested fixes per this community:

1. Tried repairing and rebuilding via Iphoto (holding down alt and command). Along, w repairing the thumbnails.

2 Tried rebuilding library via Fat Cat Software. Those 100 photos were identified with errors and were not included in the rebuilt library.

* I have the pix's backed up via an external hard drive

Question: is their anything else I should try? Or are these pixs just not recoverable?

Thanks for the support

GC