I have a suggestion where we just need to put an ExternalUrl field in PictureTable and if record is not null in this field then nopCommerce should try to load image from the mentioned Url in this ExternalUrl field.
This way it would be easy to minimize space used by file system or database that is consumed in storing image data and it will be very easy for anyone to load images from any external url such as GDrive, Dropbox, OneDrive, CDN etc.
Best Regards,
Atul Rungta