As for the picture, translations of the captions should explain all:
Here is how a man and woman should fight each other, and this is how they begin.That is correct. Trial by Combat was available to women—at least, it was as late as 15th century Germany. Supposedly, this was a method used by married couples to settle disputes...serious disputes. Since men were considered the superior sex, something needed to be done to even the odds between them, hence the hole in which he stands, reducing his mobility. Note also that they do not use cutting weapons: their blunt instruments are intended to bludgeon the opponent into submission, not cause the opponent to bleed to death.
Here the woman stands free and wishes to strike; she has in the cloth a stone that weighs four or five pounds.
He stands in a hole up to his waist, and his club is as long as her sling. [source]
Remember that non-aristocracy had to seek permission from a court to engage in a lawful Trial by Combat; hence the term "judicial duels." Husbands and wives could not just decide to dig a hole in the front yard and fight it out amongst the neighbors. There are no known recorded examples of such trials or their outcomes, but the casual way in which Talhoffer describes his sample fight (there are more illustrations in his manuscript) suggests that there was nothing shocking about this in his time.