My theme uses 8 different thumbnail sizes. I imported my local installation to the final server using phpmyadmin to export the wordpress database. Everything is smooth except for the attachments: many post thumbnails are broken. The file is there and displayed, but at the wrong size. When i open the file in the media library or in a post 's "Add image" interface, it displays that the image size is (0x0).
Only solution i find was to delete each post image and reupload it. Then it works, so it's the database import that's provoking the error.
I don't get how this error happens. Any idea? And how to fix it? The "Rebuild Thumbnails" plugin doesn't solve it unfortunately.