I think I found a solution, even if it's a bit cumbersome. Before you begin, have a list of the images you want for your product in the order you want them to appear. For example:
Image 1 (primary image)
Image 2
Image 3
Image 4
Go to your product page and then to the image tab.
Remove all of your images (except the image you want to be starred for the primary image) from the product. Click "Save and Reload"
Then, look at your list, and going in REVERSE order (begin with the image you want to appear last), click the checkbox of the image that is last on your list (In the example, this would be Image 4).
Click "Save and Reload". This will add the image to top of the list, but after the primary image.
Then add the next to last image (Image 3, in the example). Click "Save and Reload" to add the image to the top of the list, but after the primary image.
Keep doing this until you have added all of the images (all the way to Image 2)
As I said, cumbersome, but you can do it in the product page of the admin console.
