One frustration with studying visual memory is that we have no way to directly experience what someone else sees in their mind. When trying to understand individuals’ memories about uncontrolled events, we rely mainly on verbal descriptions of visual memories and individuals’ feelings of confidence in the clarity and vividness of those memories. There is a lot of variability here. Some people believe that their visual memories are as clear and high-fidelity as a photograph (though there are very few examples of this fidelity being put to a convincing objective test; see this article for an overview). Other people report experiencing no visual imagery at all (see here and here for descriptions and discussion), even when asked to imagine something that should be extremely familiar. Most of our experiences probably fall somewhere in between these extremes.
My student Gintare Siugzdinyte is currently studying individual differences in visual imagination experiences, and hoping to attract a large and diverse sample to respond to a short questionnaire. Later in 2017 after we have analyzed these data, I can provide an update about what we learned about visual imagery from this survey. You can find our survey here. Thanks very much for your help!