Logo in form description

There is an option in the description box to add a logo, but when I go to the live form it’s just a blue question mark. Can you tell me what kind of image icons put there so that it shows up correctly?

We will be glad to help you with your concern. I have checked the most recent form you have updated and see that you have successfully uploaded a logo in that form.

Perhaps you are referring to another form? Or, if I misunderstood your concern, please feel free to let us know and give us more details.