There is no easy way of doing this. You do have a few options, though.
- You can deploy the image to a new VM and then use PowerShell to fetch the installed software by doing a remote command to the VM. You still need to upload the result to a place where you can see it, like a storage account.
- If you don't want to run remote PowerShell on the VM, you can download the VHD file from the VM created and then mount it locally and fetch the information.
Neither of the above solutions will help you get any source files for installing the software on a new image. You must get those installation media elsewhere and set up Packer to install it into a new image.