The Windows Technical Preview will be an iso file

[javajolt]

Neowin was able to get another screenshot of an advanced Windows Technical Preview download page.

The other thing they are reporting is the size of the downloads.

Apparently, the 64bit version will be approximately 4 gig and the 32 Gig version will be approximately 3 Gig.

On this page, we also see that the files will be ISO files i.e. compressed image files.

We are once again recommending that as long as you plan to just play around with a preview version of Microsoft, you need to use a VM.

source:windows9update