You really have to get a hand-microscope...one that has it's own light (radioshak carries them for $15). Of all the guessing we have to do while growing, when to harvest is pretty straight forward. Get the above mentioned microscope and look at your trichs. If they are clear or cloudy, they're not ready yet. If they are cloudy with some turning amber.....it's time.
Just by looking at your pics, I would say another week.