Cant download full size images from icloud photo

Hello, I have recently uploaded all my photos to icloud, and I am now using icloud for my photo storage. Local file copies on my mac (OS 10.12.3) are not full size.

However, I would like to have all the full size files on my mac now. I have selected this option in iphoto 'download original files', however the library has not grown in size. When I go to open an old photo to see the full size version I get an error message saying cant download. The original library with all the full sized photos on has been deleted (it was on a portable harddrive).

My question is - are the full size files on icloud? When I go to icloud on my browser, I can select an old photo there and see the full size version. Thanks