Is it possible to add automatically an image on the back when the user adds one on the front view? For example, the user adds a image on the front of a tshirt and it will automatically add another one on the back?
You can try that with the "Replace in all views" option in Settings > Element Parameters > Images. Therefore you have to set a placeholder image in both views and give them the same replace value in the product builder.
But that will only work if the image is the same one. It would be nice to add a feature to add different images. For example, if I add a dress on a doll, it would have an image for the front of the dress and other to the back.