I didn't get it
I have taken one of my screenshots....
But it looks a bit unfinished.
I know I can fix it, but don't wanted yet:
Here is how it works:
Open up the picture file you want to have as background.
Select all, and copy it.
Now close your picture prog.
Open up the two files called dlgstd.bmp & dlgstdtrans.bmp in your <fsdir>\Uires.
But make a backup before!
Now paste your copied picture in here. You will maybe need to resize your pasted area.
Save!
Now you can start FS and you will see something like above.
You can't just replace them because I think it's something like 16 bit or maybe only 8. standard pictures have 24 I believe.
This bad-looking thing in there is because of several other files in this folder I will also need to change then.
I haven't figured out, how it works to get a good result, but I'll try in the next days. Oh no I'm away from tuesday to sunday.
So then next week.