Hi Mark,
This looks like you have a bit of data compression going on here. It's relatively easy to fix.
Go into Content Manager and then go to settings. In there, (I can't remember exactly where), uncheck file compression so check the options...
Setup a filter to show installed assets, but not built-in.
Highlight a bunch of them, perhaps a screen full at a time, open them up for edit and then commit them again. Repeat until all of your assets are processed this way.
Once this is done, you should be all set.
John