As since a while now, a lot of different sized LCD screens are existing & a lot of screen resolutions are avaible trough display cards, most Wallpapers creators are uploading several sized wallpapers.
I think they all do a first one in one resolution and then resize it in different ones .jpg with software ...
There's no trouble when appling as a wallpaper ... BUT, (i think), if the original one is not made in 1280x1024 px, it brings a weird trouble when doing a LogonXP with it 
After having done a resizing to get the upper bitmap, the lower bitmap & the center bitmap (and whatever settings are made in LogonXP), even if everything's seems to be correct when creating the Logon, when applying it, a lot of "white" pixels are appearing in the center panel when in use
.
I've experienced that trouble with 95% of wallpapers since a while, on whatever of my 4 different screens & on whatever PC i'm creating the LogonXP ...
Though:
1°) would be cool if all Wallpapers creators bring an original 1280x1024 made with their uploads
2°) anyone from Stardock and/or LogonXP creators and/or wallpapers creators have any idea of what's going on ??
Example :
1°) everything's fine when creating the Logon (resized fistly the Garnet_Wall_06_2560x1600 to a 1280x800 bitmap ==> should work on all 16/10 screens resolutions, set upper & lower bitmaps to 1280x100, set centar bitmap to 1280x600, set all bitmaps to "stretch")

2°) ... and here what's showing the Logon in use ... :
