Images and videos which do not have a "CreationDate" tag in its EXIF data heavily rely on the "DateLastChanged" tag in order to be sorted correctly. WhatsApp for instance does not ship that CreationDate tag with its media files.
This leads to the problem that images without this important EXIF data entry cannot be downloaded without the loss of any date information (because all other tags are changed to todays date).

The idea is to set the "CreationDate" EXIF data if a media file does not have it at download time. It should use the "DateLastChanged" date for that. That way all images do have the right date information for correct sorting.