In order to customize the image that appears at the top of your ChapterBuilder form you must be using one of the paid versions; this includes Lite, Standard and Pro. To upgrade your account simply go to Settings > Upgrade. There you can select a plan.
If you have an upgraded account, you can change your form image by completing the following steps.
Navigate to the “Forms” tab (located on the left hand side navigation bar).
Locate the form you want to work with and click on the options icon (3 dots next to the view button).
Select the “edit” button.
There you will see the ChapterBuilder icon at the top of the screen and a “Choose File” button to the right. Click on that to select the image you want to upload and to appear at the top of your form. (see screenshot below). Once you select the image it will appear.