Photos from things from home also help with anxiety.
There is software available to create resources to support communication through symbols, such as Communicate InPrint. This kind of software is more commonly used in schools; it is accessible at home but at a cost.
If you don't have or can't access something that creates symbols for you, photos work just as well. They can be used with or without words, depending on what your child needs and understands. You don't need lots of pictures either, start off with basics like 'drink', 'snack', 'toilet' and maybe a favourite toy. For a child who can't communicate verbally, pictures are a lifeline and will ease frustration for both parent and child.
You can tailor visual resources to the individual needs of the child. For example once they can master using a picture to ask for a drink, try offering a choice with one picture of a cup of juice and another of a cup of water.
Another way to use photos is to create a visual sequence of tasks that your child may find difficult to remember, for example photos of what needs to go in their bag for school.