Move the "Display only uploaded images of attribute combination" checkbox to the "Product attributes" block. Place it below the "Attributes" and "Attribute combinations" tabs
. Rename the hint of this checkbox to "You may choose pictures associated to each product attribute value or attribute combination (these pictures will replace the main product image when this product attribute value or attribute combination is selected). Enable this option if you want to display only images of a chosen product attribute value or a attribute combination (other pictures will be hidden). Otherwise, all uploaded pictures will be displayed on the product details page".
Remove the setting from the advanced product editor settings. It'll be displayed in the "Advanced" mode only
We've implemented the following task in nopCommerce 4.70 - "Multiple pictures associated to product attribute value and product attribute combination"
Let's refactor it: