OK, that is an additional image, which you apparently didn't intend to use.
Your main image for the product is named LS_P365TemplateSet2.jpg; that is the file that the product "owns", and any image starting with that exact name will automatically be considered an additional image for the product. You need to delete LS_P365TemplateSet2CU.jpg, or if it belongs to another product, rename it and re-upload it for that product, avoiding conflicting names.