Backing up files

Pages and images are handled separately:

Pages are packed together into a zip file and downloaded.
Images are packed together into a zip file and downloaded.
- As an alternative one can use "Differential backup of images" where one specify a previously downloaded zip-file. The modification dates and sizes of those files are compared to the remote files and those file who haven't changed are reused (and packed together into a new zip-file)
  - However this feature is not as fast as it could be if one used a c-program to do the same instead.

(metadata).zip

Contains site.csv, page.csv, image.csv and redirect.csv files with meta data.

I'm considering to use my own packageformat My_archive_and_compression_format_with_json_compressed_meta_data, where one can add own metadata in a simpler way like hashcodes, unixtime, access rights ...