shrinkwrap ("decal") around entire object? I just want to (shrink) wrap a plane with an image over (around) the entire object, not just one face / plane. 

[EDIT, after two answers] Many have said that original question is unclear. So now that I understand what I was asking %-/, here's the translation:  

How do I cover an object with a picture without using UV Mapping -> unwrap?

[EDIT] Skip down to the accepted answer from Duane Dibbley.



Perhaps superfluous details, an example of an only partially successful attempt:


Start Blender with factory defaults (will use default cube).
Create Plane.
Drag drop some arbitrary image onto plane. 
Set parent of plane to cube (via drag drop plane to cube in Outliner). 
Click plane. 
Add Modifier: Shrinkwrap. 
Set target to cube.


At this point, it's just on the top face of the cube. How can I get it to cover the entire cube (all faces), e.g. "folding" it around the whole thing? If this turns out to be more complicated, e.g. requiring some UV / mesh mapping things, can you please point out a link or two that might assist?  (I've looked a bunch of tutorials, blender wiki, and blender docs (which I wish had examples, not just parameters :)), but I seem to be denser than that cube! Thank you! 
- H

[EDIT:] Requested Screenshot --- the "brain" should cover the entire cube, but not multiple same images on each face, i.e., the cube should look like a brain in the shape of a cube.
It is completely unclear to me what you are trying to accomplish, or why you want to use the tools proposed in the question. So I'll post an answer as blindly as trying to break a piñata:



(photo: AlejandroLinaresGarcia, Wikipedia)

If you want a cube with a texture, use the texture directly on the cube using UV coordinates:



If you need the cube to have different front and back, the images mapped have to correspond with those views:



To have some geometry converted to the shape of another, then you'd use the shrinkwrap modifier. Have the brain object be larger than the cube, the you can shrinkrwrap it around the cube using nearest surface point:



Brain model by mahesh downloaded from  http://www.blendswap.com (login required)