None of my pictures are showing up once downloading Anki again on a new computer

I recently got a new computer (Mac) and just noticed that none of my decks have their original pictures attached. Instead just pops up a small icon with no media. When I checked the media, it says I have 28481 missing files. How do I recover these from my old computer?

In addition, I noticed these files are not on AnkiWeb either. I tried syncing many times but it was taking forever so I aborted. Should I just let it finish syncing?

Thanks,
Claire

Make sure you’ve checked “Synchronize audio and images too”.

Yes, that box is checked on both my old and new computer.

Please see Media files may take time to sync - Frequently Asked Questions