It’s already possible to upload entire folders to your picdrop account via an FTP connection. The uploaded files and folder structure will then be reflected 1:1 in picdrop.
You can find your FTP login details and a guide for the most common FTP programs here.
However, please note that because FTP is an old technology, uploads via FTP are generally slower than using your browser.
The reason we no longer activate FTP by default for new accounts is that we are currently re-evaluating both FTP and our Lightroom plugin. We’re actively exploring suitable alternatives to both.
It’s possible that picdrop will no longer rely on FTP in the future, but instead move to a more modern and appropriate solution.