Why do websites have images? They up space on pages, take time to download, and are costly to create.
The reason is, I think, because our brains process images far faster than text.
An ecommerce website selling red and blue shoes has text to tell you which is which, but they also have images. They know that we make really quick, snap decisions when we process information visually.
Images on ecommerce websites are an easy and obvious example, but images serve other purposes too. They can help set the emotional tone of the website, direct people’s attention, and provide information. But overall, all images on websites serve the same purpose; they provide mental shortcuts.
So, what might happen if we put the wrong images on a web page? Obviously wrong images, like red shoes on the blue shoes listing, might create confusion. More subtly wrong images might create harder to grasp dissonances that feel wrong in ways we can’t explain. Images of people smiling on a web page about funerals, for example.