Is 'Seeing is Believing' is justified?

To what extent the claim Seeing is believing is justified?

At first, I believed that this claim was unjustified, but after some thinking I changed my opinion. I changed my mind, because believing does not mean that the thing seen is true. For example, in 1996, in the city of Varginha, Brazil, three young ladies claim to have seen a creature with red eyes in a park of the city. Many people after this claim stated to have seen lights in the sky and even the same creature. Authorities from Brazil and from United States came to the city just to discover that 'the creature' might have been a peasant covered in mud. Nevertheless, those girls and many people in the city still believe they've seen an alien, therefore seeing is believing, even though this is a false believe.

This led to the question, what role imagination has played in their eye sight?

Thinking about it and discussing in class, I came to the conclusion that to see is different of vision. Seeing is how our brains perceive the vision of the eyes, so it's not purely vision, it's a mix between vision, imagination and memory. In a society that has never created the concept of alien, those girls could never have imagined seen an alien. Therefore, seeing is more than just vision.

Moreover you can believe in something you could not see. For instance, most God believers have never seen God. Another example, is the story of Junko Morimoto, a survivor of the atomic bomb in Hiroshima. She describes that the light of the bomb blinded her for a moment, and when she could see again she was blocked under the ruins of her house. Not seeing what happened does not (obviously) mean she doesn't believe this actually happened.

My final conclusion is that seeing is believing, but believing does not require seeing. In addition, seeing is not the same as vision, as it includes imagination and memory.