Are there any codes that use pictures instead of letters?

The beauty of secret codes is that you can be as creative as you want when making them! So if you want to use pictures instead of code words or letters to represent a certain word or phrase, that can definitely work. For example, an apple could be "Hi," while a cat represents the word "walk." It's likely best if the picture doesn't explicitly represent the word (i.e. a picture of a bee actually representing the word "bee"). The more abstract the pictures are in relation to their meanings, the more difficult your code will be to crack.