You can totally hide a slot that is already open. A normal frame has some layering going on in the back anyways: https://www.universityproducts.com/pub/media/w

You can totally hide a slot that is already open. A normal frame has some layering going on in the back anyways: https://www.universityproducts.com/pub/media/wysiwyg/how-to-images/framepackage.jpg https://www.universityproducts.com/pub/media/wysiwyg/how-to-... All it would take is a slot in the frame back and a bit more sturdy backing paper covering it. The backing paper that has to be not fixed on the bottom edge.