I just migrated my blog into a multisite network. I managed to get mostly everything working, except for post thumbnails. They seem to be unattached, and I can't figure out which DB record does this. When I go to "Set featured image" screen, I see all the images there and I can set the featured image, but I don't want to do this manually for each post obviously. The postmeta table is the same as on the old website. They both use the same domain name, so the image paths are still valid.