I suppose the underlined word is "fortitude". The word that most closely defines it would be strength. Fortitude means courage in a dangerous or adversary situation; endurance, resilience. This passage draws on the traditional, patriarchal prejudice of women as frail, weak creatures that have to rely on men for courage and strength.
I think it's "Pictures display information when written instructions are more complicated". Personally I believe it's just a majorly confusing way of saying: when the written instructions are too complicated they use pictures as well.
