...No pain here !
Now the previous part of the code that I have posted was a modification for testing CAD in a Winamp + album cover skin that I made and use in my sidebar to replace CAD, and it had a transparent background image.
It almost the same thing apart the process is winamp.exe, to have the Winamp icon colourful when is "on", and colourless when is "off".
I don't know how your .ini file look like, so I have done a skin for the cad image and it work o.k (hide the image and you could drag it when the image is there), but if I remove the [MeterBackgroung] in it, the cad image will not be hidden, and could not be drag when cad is "on" like you said !
Here the skin so you can try it !
And here you can have a look of my Rainmeter Sidebar with Winamp + album cover skin...