If you's just using a USB stick to flash the image then yes thats correct just copy the gigablue folder and it's contents to the USB stick if using the image manager however you need to go one more level up for example.
I use 7zip. I highlight the file with the right hand mouse button then select extract to openvix-4.2-vusolo2_usb ( for example ), it's this folder i then copy to the image manager.