No interior photos? 
No need to visit that house!

Some sellers find it absurd that a buyer would have this mentality as they decide which homes to visit --- they assume that if a buyer is serious, they'll come see the house for themselves even if there aren't any (or very many) interior photos.

But buyers are smart, and make reasonable generalizations: most homes without interior photos are hiding something.  Perhaps it is the awful condition of the home, or the hideous decor, or the tiny rooms.  In most cases where only one photo exists for a house for sale, there is something that the seller doesn't want to have highlighted for the world to see.

And thus, as busy buyers pare down their list of homes to view, they will often assume the worst of houses that do not have interior photos.

Sellers -- you don't need to go overboard with how many interior photos are posted to the MLS or other web sites, but do include some interior photos so that prospective buyers can have at least some idea of what to expect.