Flash CS5 Reverts Updated Images

I have yet to find a fix for this, but seemingly without reason, sometimes when I open an FLA file, I find that a few jpgs that were previously imported and then updated with another file, have reverted back to the original imported state.

If anyone else has had this happen, or has a fix, please let me know. I cannot find another instance of someone else experiencing this online, so it would be good to know I'm not the only one.