Images are distributed here so that mirrors can pick them up in time before release. Images here may not be final even if they look as if they are; by distributing pre-release images here we can make final mirroring faster.
Please do not attempt to download images directly from this directory; by doing so, you are likely to contribute to delaying the release for everyone else, since we will have to wait longer for worldwide mirroring to complete.
-- Ubuntu Release Team