Current mood:

embarrassed

Answers to The Picture Frame
Are below

Q1: Tension = 1.74
Q2: Vertical = 1/2 upward each. That's what supports the weight. Horizontal = 1.667 inward.
Q3: Same as Q1. The tension is determined by the angle CBA which is the same in both cases
Q4: Vertical = 1 (approximately) downward. Horizontal = 2.55, greater than before because there is a contribution from the tension in the (B or C)-to-(D) segment. This is where it starts to get interesting. Instead of being pulled up, posts (B) and (C) are being squeezed downward (and even harder inward) by the tension in the wire. Net force on a side post is now 2.74 where it was 1.74.
Q5: Vertical = 3 (approximately, upward) and horizontal = 0. The anchor point (D) is bearing a force equal to three times the weight of the frame.

Extra credit: That all depends. If they thought they were reducing the stresses on the posts, they failed miserably. If they needed some compression to keep the bottom of the frame from bowing downward, they got it - in spades.

p.s. This is trickier than it seems. I first posted a wrong answer!