Which firmware file should be downloaded to upgrade a vSRX running in Azure - the .tgz package or the .vhd image?

For upgrading the firmware on a vSRX running in Azure, you need to download and use the .tgz Junos installation package.

The .vhd file is used when you are deploying a new vSRX instance

For upgrade → use .tgz

For fresh deployment → use .vhd