Originally Posted by Ledgem
How are you verifying free space? Occasionally the Finder lags a bit in updating how much free space you have, but third-party programs tend to be even worse. If you're using a third-party program to verify free space, there's also the chance that the deleted files are now being marked as local backups; third-party programs do not view this as free space but the Finder does, since Finder will delete the backups over time and overwrite them if other data needs the space. In that case, it is essentially free space.
One other possibility is that you're suffering file system corruption and the system can't accurate gauge free space. Run Disk Utility and "verify disk" on the partition that housed your photo library. If there's corruption then fix it. If the corruption exists on your operating system drive then you will need to reboot into recovery mode and run Disk Utility from there to make the repair.
Thanks, I have rebooted into the recovery mode, and run/fixed the disk problem. Same diskspace as before.
The disk space issue has been two days, so it must not be the Finder lagging issue.
Any good filesize tool recommended? Like the Treesize under Windows.