Deleting files on my external hard drive

I have a WD My Passport. I received it as a gift to store my tons of pictures. I thought it would be a good idea to also use it to store my backup for my desktop. After I backed it up it pretty much filled up my drive. I now want to erase the backup and just continue using it to store pictures. How do I erase the back up files of my passport so I have room for my pictures?

The main question is, how did you backup the PC? If you used Smartware, make sure the backup is disabled on the PC and then delete the WDSmartware.swstor folder. If you used WD Backup, then again, disable the backup on the PC and then delete the WDBackup.swstor folder on the Passport. If you used Windows backup, Turn off the backup schedule under “Backup and Restore” and then delete the folder with the name of your computer from the Passport.