Discontinued application for photos software calculator

Hello everyone,

SI have a problem and I hope that you can help me.

Almost a year ago, I installed a "secret vault" app from the apple store. The app serves to store photos in a file disguised as a calculator and the photos in question are erased from the gallery after storage. I have photos of my girlfriend and me (my mother is against our relationship and often searches my phone for photos) :(

Well, my problem is:

I no longer need to hide my photos and I tried to export them all to my gallery but I was surprised to find that there is no option to export them at all, can only done one by one.

Bearing in mind that I have 400+ photos is the app and There is only the option to import photos in bulk to the app but not export them, I am pretty desperate and don't want to lose those photos.

I tried to send an email to the support of the app, but no answer (the application seems to have been discontinued) no more updates since a long time.

I would like to know if you know a way to extract the photos via pc or something like that

The app must have encrypted them because I do not see anything via iTunes in the app file.