Q: iPhoto database rebuild

That ! means iPhoto can't find the actual file.

What version of iPhoto do you have?

Sounds like the recovery was incorrectly done

Right click on the iPhoto library and show package contents - look (do not make any changes of any sort) in the masters folder and see what is there including pixel size of photos - also look in previews and thumbnails for the same

If the recovery was done correctly there is a small thumbnail of each photo in the thumbnails folder - a full resolution copy of the image in masters and a preview (typically smaller than the master but not necessarily) in the previews folder - what you you have

Until we know what you have it is not possible to go further - and if the correct photos are not there then you can not fix that - you need to have the recovery done correctly - there is no way to fix a small photos to be a larger one

Probably the best solution is going to be to restore your backup from before the MB died rather than doing recovery from a dead machine

LN

All my pictures are intact in the correct event/album, but only as thumbnails.

To save at least the thumbnails select all photos and drag them to a folder on the desktop.