I found a way to replicate the issue (Motorola Gallery closing on launch).
If you have pictures (already indexed/cached) in a couple of folders, then you decide you want to hide the pictures in one of those folders by creating a .nomedia file in that folder using a File Explorer, it is a matter of time (next restart?) before the Motorola Gallery will close on launch.
The cooliris 3D gallery (Gallery3DMT.apk) is a little more resistant to this. It will display corresponding "blank" pictures.
Simple fix: copy the files in that folder to some other folder that already had a .nomedia file in it.
Then use the cooliris 3D gallery to delete the blank pictures.
The Motorola Gallery will now work.
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