Currently when exporting an image, the filename defaults to the painting name (e.g. "unicorn.jpg" from "unicorn.ptg").

How about the same behavior when exporting a layer from the Layer Menu (instead of "Untitled.jpg")?

Or better yet, if the layer is named, defaulting to painting name-layer name. (E.g. if I export layer "laserscope" from "unicorn.ptg", the filename default is "unicorn-laserscope.jpg".)