Customize or Remove Payment Image:
In your zen cart admin go to Tools -> Banner Manager.
Click on the banner "Footer Payments Image"
Click on the "edit" button
Click on the "browse" or "choose file" button and select your image.
Click on the "update" button.
The default footer payments image size is 206 x 23 pixels.
To remove any of the footer payment image, click on the green "status" button to turn it red in Tools -> Banner Manager.