The problem is your angel image is not a layered image - if you don't have a layered image you'd just use regular AlphaMask and not the LayeredImageMask. Layered images are declared like layeredimage angel and have a specific format that Ren'Py expects. I suggest you look into it, as it's the modern and simpler way to put together images with multiple layers. https://www.renpy.org/doc/html/layeredimage.html#LayeredImage