Copy pictures from multiple source directories

[hhzl]

The input directory data/pictures has a directory c10 with pictures. For example a picture with file name lion.jpg. Allow the user to add more directories, e.g. c12 and c16 which may as well contain a picture lion.jpg. Start copying pictures with from the lowest directory and allow higher directories to override the picture selection if the picture exists.

It results in copying all directories, c10,c12,c16.

This allows the user to start with a picture collection (c10 as default) for a start and then override pictures with different ones. So pictures are replaced by adding them in a directory with a higher number.