Sadly, unless you want to replay her route from the scratch, the only way to get them back is to use "unlock all scenes" button in the settings. This bug happened due to us changing the majority of her pictures and renaming the character itself, so good news - it won't happen again, but bad news - it's not something we could easily fix, since the problem itself lies in how our engine treats save files.
We will still look into ways to possible revert this bug, but I doubt we will able to do it in a short enough time frame.