have just "blogged" this:
I was having a discussion on another forum, and got fascinated by an observation another member had made. If you use the default desktop, the welcome screen only stayed for 2 or 3 seconds. If you customised the desktop, this deteriroated to, in the worst cases, about 50 seconds.
I began to explore the startup procedures and finally got on the track of how to circumvent this. It is a matter of paths, and default pictures. If you would prefer your own custmised desktop, experiment with this.
1. I went to Windows - Web -Wallpaper - Windows. In there is a file called img0.jpg. I copied this, for safety, in case something went wrong, to img01.jpg. I took ownership of the file (This is neccessary for the next stage)
I then opened it in my Graphics program and played with it to get the theme I liked. Then I saved it back to its original place.
2. Next I pasted this to users -username -Appdata - Roaming - Microsoft - Windows - Themes.
3. Now I opened that folder and in there was a file called TranscodedWallpaper.jpg, which I renamed (Anything you like - just add a 1 to the end if you prefer). I then renamed the file I had just imported to TranscodedWallpaper.jpg.
Exit and reboot. Now, from the Welcome screen to desktop is pretty much instant.
DO THIS AT YOUR OWN RISK - Backup first