You have not described, just copied and pasted that question, so it’s really tough to get what you want.
If you want to change the icon with image, place image there in the lock icon and removed the lock icon.
Such as replace this line
<i class="fa fa-lock"></i> with the line
<img src="your-image-url" />
BTW: please see the right sidebar notice and our office will be close soon. We will come back at 6th fabruary