No really! I have such concerns for your stupidity that I will annotate everything for you just so you know what everything is, or, if you aren’t paying attention it will become immediately apparent so you can catch up.
There is some educational theory that suggests it is helpful to “signpost” as this allows the audience to orientate themselves in a complex presentation but if your audience needs you to write down that “this is the introduction” and “this is a picture of a dog” then perhaps you have over estimated their ability to understand the complexity of the subject. Or perhaps it is just a ridiculous habit that we really haven’t appreciated is almost totally redundant and, if viewed appropriately shows an incredibly patronising attitude.