On a Windows machine, the image files should be in the Recycle Bin, and your originals are still where they started. But whatever editing you did to them within jAlbum is gone - that info is stored in a sidecar file, and when you delete an object from the project, that file is dumped.
This is why there's a confirmation dialog when you delete objects.
If you ask me, a Photo Recovery Software is not the solution to the problem. The solution is a backup is a backup is a backup. I mean, we are in the year 2020 and people don't have one single backup of their unique files? Boy oh boy