How does "image" field work?

I created an image field in my application, where I would expect we can upload product images. However, when I run the application, the image fields doesn't have an upload button associated. Instead, it functions more like a text field, where you can enter text.

So, how can I upload an image in the application?

The Help doesn't help - in the "field types" section, there is no mention of the "image" field.

Please enlighten. Thanks.
cambridgemta