Here is what I think you mean:
Can you use sketchup layers with 2D entities like you do in photoshop? Not exactly, but you can approximate this, and it doesn't necessarily require Layers Manager, unless you want to independently control the visibility
Example

1. import 2 2D images into your Sketchup drawing
2. assign each to a different layer, like Layer0 and Layer1.
3. assuming you're viewing from the top, select the 2D entity you want on top, then
4. Select move that entity up the blue axis so it is physically on top of the "lower" 2D entity.
5. Now you can control visibility of each image entity with layer manager.

CCK