Thank you for the feedback. I apologize this took so long to respond to.
We have quite a few widgets that will assist you in uploading files in one way or the other. This is because each widget is function specific to meet one particular need for your form.
We designed this widget specifically for this purpose: to preview images as you upload them - which is why the widget seems feature-limited.
To remove and add a different image, just lick on the upload button again, and the current preview will be cleared:
I certainly hope this helps - but I would like to your your thoughts concerning my response.
Thank you for your patience.