When you work inside Pics.io app you can upload new files, add revisions, create collections and do many other things with your digital assets. To keep the same structure inside the working folder in your Google Drive, automatic sync from Pics.io to Google Drive is performed by the system.
The changes made in your collections and digital assets are pushed to the working folder in your Google Drive.
All metadata from standardized EXIF/IPTC fields and individual custom fields is safely stored within your assets in Google Drive. The title of your asset, its description, all kinds of marks such as color, star rating, flags, and other information from your custom fields you may have entered in Pics.io - all this information will remain available even after you download your asset and work with it outside Pics.io, e.g. in Lightroom or in a similar service.
The revisions you upload are attached to your assets, so the latest revision will automatically appear in the working folder in your Google Drive. Read more about version control here.
If you delete some assets inside Pics.io, these files are not really deleted. Pics.io simply moves them to Google Drive trash folder, from where you can easily restore them if necessary. Read more about deleting files from Pics.io here.
As the sync from Pics.io to Google Drive is made automatically now, we have removed this option from the account settings. Still, it is necessary to perform a sync from your Google Drive to Pics.io for all the changes made in Google Drive to be displayed in your Pics.io account. Usually, the synchronization happens automatically by the system. But in case you want the updates made in Google Drive to appear in your Pics.io account right now, manual sync is required.
You may check more details about Sync from Google Drive and Auto-sync feature here.