When editing the order form for a product, there is several ways to show images.

The most important image is the product image, it is set in the Selling menu of the product. The product image appears on the right hand sides on pc, and on top on mobiles. The product image is also used as icon for the product on the customers account page.

Orderform view on pc:

Order form view on mobile:

If no product image is uploaded then the logo is used instead, the logo is set in the account Settings under Colors and graphics -> logo for white background.

If you don't have a product image and don't want the logo to show instead, then you can disable it by ticking the "Do not show the logo..." box under Order form -> Custom copy. The logo will still appear on the top left of the order form 

To sum up, product image is set under Product -> Selling, custom text on order form is set under Product -> Order form -> Custom copy, the option to turn off the logo when having no product picture is placed at the bottom of the Custom copy section. The logo is set under account Settings -> Color and graphics -> logo for white background. You can see where to set things up in the picture below.