Microsoft have updated the Windows 10 ISO download files to build 14366 the same as the current slow ring version. The ISO files are handy for manual installations and especially useful if you are having problems getting the preview builds to download.
Build 14366 was released to the fast ring back on June 15th and doesn’t include new features but there were a lot of fixes (see my post).
You can grab the download from Microsoft and here is my hands on video from June 15th: