Walmart Error - Code: IB_ARRAY_MINITEMS Field: productSecondaryImageURL Description: 'productSecondaryImageURL' requires '4' entries. Enter the minimum number of fields.

When you see this error on your listing, it means you do not have enough images.

 Listing Mirror sends one of your images as the Primary Image. Then it sends the rest as Secondary Images. 

So if your listing has 4 images, that means Listing Mirror is sending one image as the Primary Image and 3 images as the Secondary Image. 

According to the error above, you will want to add one more image to your listing to meet that "4 Secondary Images" requirement.