There are mainly two factors to consider, one being the transform, second being number of backgrounds.
The interpretation of multiple background image data vary by the target frameworks.
For instance in CSS, you can use multiple background images by separating them with comma, but in Flutter, you can't.
Even this vary in the same framework, if the image has a transform applied to it.
For more info about how we decided to handle multiple backgroun images in each framework please read the following articles.