Moving it to PSE forum
By default, the photodownloader creates a folder structure named by dates. You can change that behaviour in the Organizer preferences (camera or card reader).
Chances are that what you are seeing is not the files names, but the names of the sub-folders including your files with their original names ?
If file names are missing from the thumbnail view, go to the View menu and ensure that Show File Names is checked.
This was the solution. Thanks very much.