A very nice way to back up your files is using git:

1. Go to the directory you want to back up and then initialize it as a git repository: git init
2. Optional: create a file called .gitignore and add filenames that you don't want to include in the backup.
3. Add the items you want to back up: git add my-images/ code/ secret-documents/ stuff.txt (this could take a while)
4. Make a commit: git commit -m "backup my files"
5. Bundle the repository: git bundle create Backup.bundle master (this could take a while!)
6. Upload the bundle to a safe place.

To restore the contents of the bundle: git clone -b master Backup.bundle

That's it! Now you can do incremental backups of selected data into a single compressed file.