I noticed that the 2nd featured image (the product image that is shown when you hover over the product image) is showing weirdly. This is because there is no layer when it happens, so that the png file shows on top of the old image which makes it look really weird (see screenshot). 

Is there some CSS or something I could do to fix this? I really don't want to convert so many images to .jpg and re-upload to fix it. 

Thanks

I think I fixed this with CSS. Please see if it is the correct approach:

.products .product-inner:hover .product-image img.woo-product-hover {

background-color: white;

}