The final size of the .nb file is 655360 The size of the .nbh file is entirely different so yes, the one posted is safe.
Thanks navyguy, I'll add it up in the list!
The best you can do is open the original windows splash file, copy and paste the picture you want, then save it. It seems you're doing it in a wrong PNG format.
Thanx m8, that was a good idea, that helped me alot. Now the resolution is good, but there is another thing. I still see the start bar above the screen. If you now also now a solution for this, that would be great.
Otherwise I just leave it like this...