review an image before it is uploaded
<form runat="server">
  <input accept="image/*" type="file" id="imgInp">
  <img id="blah" src="#" alt="your image">
</form>
    <script type="text/javascript">
        imgInp.onchange = evt => {
  const [file] = imgInp.files
  if (file) {
    blah.src = URL.createObjectURL(file)
  }
}
    </script>
