We have had an issue where users are upload files after changing the extension. For example we will find file uploaded with .jpg or .tiff which were actually pdfs causing them to not display properly when loaded in the web client. 

We were going to add the image preview option to the upload file option in forms but found that this does not display tiffs. 

Is there a way to get the image preview of the file upload in Forms to display an uploaded tiff file, or is there another method to display the uploaded file before they submit? or is there a way to verify that the content of the file being upload matches the extension of the file for jpgs, pdfs, bmps, and tiffs?