Have you ever dreamed after having applied some modifiers to an image to put this exact result in some kind of Blending Mode over the original image ? Well overlay is there for that !!! Lucky little bastard. On the example below you see 2 groups of modifiers (identical). One is applied directly on the image (left red square). But this image look smooth like it could be applied as multiply blending mode over the original image to do a nice effect. Well, then just create an overlay modifier, set it as "multiply" as on the image below, drag and drop your modifier or group of modifiers and there it is!



As you'll see, the blending mode of the Overlay modifier is exposed inside the Element Tree, as any Layer :


Also Note that more complex setups can be done in the same philosophy with the Compo Based.