Although the word "said" is not necessarily wrong, it is imprecise and informal. Therefore, it does not seem to be the best word to use in this sentence. A more formal and clear word is needed, such as "communicated," "reported" or "stated." On the other hand, the words "findings," "study," and "conclusive" are both clear and formal.
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.
