New
#21
On the Win10 previews, MS would typically release an ISO when the build was released to the Slow Ring users. For production stuff, MSDN is a pretty good indicator because new ISOs will almost always be made available through that distribution mechanism (msdn.microsoft.com). On the other hand, the Windows 10 Download tool (Media Creation Tool) appears to be getting updated with new ISO images each time they come out, so that might be another good place to start looking around.
HTH,
--Ed--