My Passport Essential

I just bought  My Passport  Essential  for Mac. I have not taken it out of the box yet until I find out if this is going to work for me. I have thousands of pictures on my Mac that I need to backup on the Passport. However, I would like to then delete almost all of the pictures that are on the computer while keeping the copies safe on the Passport.  Can I continue regularly backing up without the pictures being deleted on thePassport? In other words, I want to use the My Book for a regularly scheduled backup task without losing any of the pictures that were backed up at an earlier date but are no longer on my computer. I appreciate anyone that may understand what I’m asking and provide me with an answer. I know I can use an external hard drive to store my pictures but I really want Passport  to regularly back up everything on the Mac. Or  do I have to have 2 different Passport drives?

You can backup and delete the files from the computer, bare in mind that you have no backup and will be only using the drive to store the files on the drive. Even when the files are not on your computer the software will not delete any files since the software is only build to add not to delete.

I recommend having to drives to ensure you have a backup if something happens to one of the drives.