Hm... that'S crap =(
But there's still the option to use batch-conversion o_o
S-spline doesn't support this feature, but Photoshop for sure.
PS doesn't have the Spline-option, though, but bicubic should work quite good ionstead.
Bicubic-stretching brings up some blur, but this could be fixed with "unsharp mask" (don't know if this is correct, it's called "unscharf maskieren" in the ger version)
A small contrast-correction should be fine, too. (Sry if this is wrong, I never got that "to <> too"-thing at school .__.)
I don't even know how good the result would be, but I guess it would help a little bit, because the images would'nt be stretched so much during the highres-procedure.
I guess I want to give it a try o.o
So, where are the BG-images stored ?
And: Can I open that file with LPG-tools ? o_o