Spirit communicate with all means they can, they will use all of the mediums senses, to get the message across. Yes you can have smelly vision with Spirit and taste a vision as well. Clairgustance is the ability to taste things that are not there. Clairofacrience or Clairessence is the ability to sense smells which are not physically there. Clairvoyance is the ability to see spirit, Clairaudience is the ability to hear spirit and Clairsentience is the ability to feel or sense spirit.
The one thing that tends to get left out is understanding. You can just know what spirit mean without words, pictures, sound, smell or taste. Spirit tend to refer to this as clear seeing.
How do spirit get these things across to you. They use your imagination, so when we say I wonder if it is my imagination well it is. So do not try to stop your imagination by blocking that communication. As you gain in experience you will know when someone is communicating with you and you are not dreaming it up yourself because you will sense them near you in some way.