The default wallpaper for the HTC Widget HD is just a black background. However, you can choose to insert your own wallpaper. This can entirely be performed using iFile:
1. Copy your wallpaper into this location 'var/mobile/Library/Springboard'.
2. Rename your wallpaper as 'HomeBackgroundPortrait.jpg'.
3. Respring.
In my case, I like the default wallpaper '100.png' (the one with the bubbles) and it can be found for my iPhone in the directory 'var/stash/Wallpaper.ajkUws/iPhone'. The screenshot is illustrated here.
