Why does it show a broken image icon when I add an image into gravity forms?

Question

I wanted to add an image to a form. I am using the gravity forms plug-in on wordpress.

Followed the instructions here : https://www.gravityforms.com/blog/how-to-add-images-to-a-form/

However, it resulted to a broken image icon. Need help.

Code used on the HTML field was : <img src=“Paste Image File URL Here”>