@Ashley I think Miu3 is talking about being able to export an image of the entire layout at edit time, so a save at disk rather than download. From an artist perspective this can be quite useful for level design workflow.
I can see such feature working together with the ability to set an image as the layout background for reference when placing the objects precisely according to a previously designed level. Something similar to the background image that Blender can display in 3D view. It's currently possible to do this with a big sprite, but a more optimized feature that doesn't choke with giant images and doesn't interfere with previewing would be better.