File appearance in folder has changed

Over the past week, saving files to my folder have changed in appearance. In the view icon option, files use to look like a small photo of the document. Now , it looks like a generic file icon. For example, the first page of one of the document was a photo. That is what I saw when I looked at the file. Now document is saved with the appearance of a Pages icon. Is there an option feature I'm missing that allows for the view icon option to restore the viewing feature so that my files look the way they did before the generic icon look for all files?