This aseprite script creates an outline for multiple layers as if they merged before being outlined. (It does NOT actually merge the layers). The outline is created on a new layer named "Outline"
Note: aseprite's default outline function will create an outline for each layer individually, this creates an outline for all the layers as a whole
1. Install
Just download Outline Merged.lua and drop it into the scripts folder
Observe there is no change to the original layers, making it easy to undo
Notice that outlines are only created in the frames with selected cells