When adding files to folder assets on my site, the file sizes always read between 300 and 400 bytes. If I edit one of the files using the admin panel and then just click "Save", WebGUI corrects it. This happens when using File Pile, the import Perl script, and (I'm pretty sure) adding files as assets in the asset manager.
Update:
I uploaded some more files to try and narrow this down. Seems that the size is correctly displayed *until* the version tag is committed. All the sizes I had "fixed" by editing/saving have gone back to 305 bytes after committing the changes.
Thanks for the update, SD. That actually helped me pinpoint one of the problems.
I'm still debugging.
Backported to 7.3.19.
Waiting on an upgrade script to fix existing installations.