Option 1. How digital data (image)is represented and transferred. For Foundation students who are learning the alphabet, I would use a visual coding system to teach them about digital data. They will convert text by decoding CVC words. This particular example is  from the Australian site “You Clever Monkey” https://youclevermonkeyshop.com/products/cvc-word-crack-the-code-cards Their are similar products on TPT or you could make your own. As students get older they could use more advanced coding activities that use the binary system.