Change install method

For years, I have been copying the full ISO to a USB stick for installation.  I just realized I should now be using the NET install image, because my Internet speed is faster than USB 2!  Until a couple of years ago, my download bandwidth was 75 Mb or less.  It's now officially 500 Mb, but actually around 900 Mb.  USB 2 tops out 480, assuming appropriate hardware.