"...While standing this way, make sure that the head, neck, back, hips, arms and legs are aligned properly..."
"...and gaze at the tip of the nose".
clear instruction for the breath,
"..Inhalation and exhalation of the breath must be slow and of equal duration". (for the first photo)
and kumbhaka (retaining the breath in or out) instruction, here the kumbhaka is after the exhalation in the second photograph.
"...Initially, when you first practise this without any support, you might fall down. In that case, after slowly exhaling the breath out, firmly hold the breath. This will prevent a fall. "
Note too that while Krishnamacharya takes the big toe in the first sthiti he holds either side of the foot in the second sthiti, (less strain on the hamstring and sciatic nerve than pulling back on the toe).