how to extract preview when you lost your original images on Lightroom Classic

"But when you say 'to restore the backups of your original images' are there an other way than with catalog?"

The LrC catalog file contains all of your editing information, but NOT the actual imported image files. In addition to the LrC Catalog Backups you need to use a separate file synchronization backup application for the image files. The LrC Catallog and image file Backup should be on a separate 2nd HDD or Cloud storage. The cheapest solution is to use an external USB 3.0 portable HDD such as the WD Elements or Passport. Here are some file synchronization applications:

https://windowsreport.com/best-windows-10-file-sync-software/

You should backup all of your Windows Library folders (My Documents, My Music, My Pictures, My Videos, etc.) and any other folders that contain media and document files.

The first step should be to restore the backups of your original images.

"erased by mistake my original images."

Check the Windows Recycle bin or Mac Trash for the deleted files.

Try this one.

This plugin works in Lightroom Classic, and older versions as far back as Lightroom 4.

http://regex.info/blog/lightroom-goodies/preview-extraction