I'll go grab those pictures and cut the background out of them and post them as .GIFs so you, or anyone else who needs transparencies for that matter, can grab them. The one thing that photoshop is really great for is transparencies.
Be back in a bit.
Edited to add:
Ok, here they are:
On a black background the Slade one will look good again, and they will all blend in better.
They all might look a bit strange if you put them on white.
Edited one last time to add:
One of the problems with the ear in the "love note" wallpaper was that the ear itself was not clear, I went through my photos and found a better ear to use, moved it in, ragged out the edge: