It might help to understand that Files and Images are stored in the Cloud based file system associated with App Creator account (unless you have turned on specific setting in the AppSheet editor to do otherwise). For instance, if you login to AppSheet using a Google account, the Google is the Cloud base service used to store these files.
Additionally, in this case of a database sourced app, AppSheet uses the Default app folder as the root folder to start searching for the Files and Images. This property is specified in the “App Properties” tab (see image below)
In your video, the error you were getting after you uploaded the file was a “404” error. In most cases this means that the pathing is incorrect somewhere. Do you any Path specified in the column definition itself? If so, try removing it altogether and then retest. AppSheet should use default behavior and be able to save and load the images.
Many thanks @Steve and @WillowMobileSys I don’t recall moving it but maybe I just have to recreate that record.
It maybe safer if I revert back to the Google Drive as a datasource and actually save the files in there and have it linked to Appsheet. All I want, is to be able to
create a preview/thumbnail of the file
be able to use Appsheet as a tool to capture photos (via camera of the phone) and files (via a simple drag and drop) into Google Drive (that later on I can move in location/rename, but will still be linked to the Appsheet column).