First I cloned out the original light bulb from the source so I had a plain wall to work with. Then I fixed the light fitting so you could see the back through the light bulb. Found a globe with an element on Google, resized it to the same size as the source globe and cut out the
element, then cloned it out so I had a globe without the element visible.
The problem with see through globes on a white background is that when cut out they are white :(
This was unnecessary, but I didn't know that yet :). In the end I left one layer of it at 2% opacity anyway.
Cloned the light globe again layer and erased the inside all the way to the edges to define them and enhance the see through illusion.
Then copied a layer and darkened it, erasing one side to give the globe more depth. Then I added a dark and light version of the element erasing some of the white to enhance the element a little. Another globe layer and erased most of it but the slight reflection so that it would be over the element.
I found an old light switch in the off position and stuck it to the wall and added the wire leading to the light. Added some shading around the bottom and the wire and merged all the layers. I wanted the wall not to be as clearly lit as it was with the light on so I darkened it a bit an shone a light on it from the left which brought out more of the wall detail.
I tried to clone out the light ray on the right side of the globe, but that was nearly impossible without it being really visible so I solved the problem by cutting out a couple of wall segments large enough to cover the light streak trying to match the shade of the wall. Once it looked ok, I just erased the hard edges and job done.
In the end it looks deceptively simple and dark and I have no idea why anyone would put it on their desktop, but it was worth the challenge :)