The default widget behavior is when a user selects an image, its preview is then shown in the upload dialog. You might want to embed this preview in your page somewhere around the widget button. Such a preview could be more informative than simply displaying file names and sizes.
See this live demo to learn how to do this.
Note, you have full control over size and position of your embed, just use CSS.
Image preview for a multi-file widget may look different:
See this live demo to learn more.
You can change the displayed images or rearrange the existing ones; all changes will then be reflected in the thumbnail list.