OK. I found someone claimed there was a method, for WinXP, to get a transparent Taskbar. Although I don't totally understand what that guy was talking about, I am still wondering if that method can also be used for Win7. Can it?
See
Transparent taskbar??? - General Discussion - Windows Customization & Support - FORUM CrystalXP.net English
The steps of that method are quoted below (I insert my questions in blue):
1. First take a picture of your desktop (without using a camera and with no windows on the screen) and save it.
That's just "pressing the 'Print Screen' key and pasting into an image editor". Right?
2. Open the image with an image editing software like Adobe Photoshop and crop out everything except for the parts on the taskbar that you want to stay opaque.
That's "making everything transparent except the Taskbar icons". Right?
(I have only used 2 graphics editing programs: IrfanView and MS Paint.)
3. Now copy your normal wallpaper into a new layer behind your edited picture of desktop.
"Copying into new layer" must be a fuctionality of Photoshop. Right?
4. Resize the picture to the size of your desktop (you can find out the size of the your desktop by right clicking on your mouse and select properties and in the properties window select the tab display settings and near the bottom there is a slider saying Resolution and under it show you the size of your desktop example 1024x768) and save it.
Why is resizing necessary? After "copying into new layer behind...", the newly generated picture should already have the same size (resolution) as the screen, shouldn't it?
5. Apply the picture as your wallpaper and there you go!