For logons that are made with Logon Studio and when you use them at 1280 now and the center panel is now tiled or too small, (usually they move to the top left of the center panel), set the center panel to "stretched" in the LS editor, save, and apply.
Usually that will work fine, but sometimes the image will show with white blotches when stretched. If that happens, close the Logon Studio editor, go to the folder for that particular logon (C:/Program Files/Wincustomize/Logon Studio), open the uifile, and change line 14 from this:
background: rcbmp(100,6,#0,0,0,1,0);//rcbmp(100,6,#FF00FF,0,0,1,0);
to this:
background: rcbmp(100,6,#FF00FF,0,0,1,0);//rcbmp(100,6,#FF00FF,0,0,1,0);
That will take care of the problem.
DON'T open the logon in the LS editor after that or LS will change the file back to how it was before.