JSFiddle - React, Tailwind, and code Playground

HTML

<div class="fileupload fileupload-new" data-provides="fileupload">
  <div class="fileupload-new thumbnail" style="width: 114px; height: 64px;"><img src="http://www.placehold.it/114x64/EFEFEF/AAAAAA" /></div>
  <div class="fileupload-preview fileupload-exists thumbnail" style="width: 114px; height: 64px;"></div>
  <span class="btn btn-file"><span class="fileupload-new">Select image</span><span class="fileupload-exists">Change</span><input type="file" id="file-input" /></span>
  <a href="#" class="btn fileupload-exists" data-dismiss="fileupload">Remove</a>
  <button type="submit" class="btn btn-primary" id="upload-btn">Upload</button>
</div>

CSS

#upload-btn {
display:none;
}

JavaScript

$('#file-input').on('change', function(evt) {
    var file = evt.target.files[0];
    if (file)
        $('#upload-btn').show();
    else
        $('#upload-btn').hide();
});