This is probably so easy, I'll be embarrased by the responses, but I just can't figure it out. Here is what I have and done now:
A clean and fully functioning 4.8 install
created a new parent portal (portal 1), copied the DNN Blue skin and container folder to same location and renamed to UN Blue
modified UN Blue\skin.css - ".pagemaster": background-color: transparent; background-image: url(bodybg.gif); background-repeat: repeat-x;
applied UN Blue skin to portal 1 site
bodybg.gif is a 12x200 px image. it is a gradient image, dark on top and faded to no color at the bottom.
Now the background is transparent, the image is showing and repeating on the x axis. The problem is that it is also scrolling on the y axis, or in other words it starts scrolling again 200px down from the top, then 400px, and so on.
Obviously there is some other code controlling this behaviour other than css. Anybody know how to fix this?