Hi Peter,
here comes a crude approach, but maybe this goes in the right direction:
img0 = Image@
RotateLeft[ (* `RotateLeft` is for fine tuning ... *)
ImageData@
ColorConvert[
Plot[0, {x, -10, 10}, PlotRange -> {{-10, 10}, {-4, 4}},
ImageSize -> 500], "Grayscale"], {0, 2}];
img1 = ImageRotate[
Plot[3 + Sin[x], {x, -10, 10}, PlotRange -> {-4, 4},
PlotStyle -> Green, ImageSize -> 500], -10 \[Degree],
Background -> White];
ImageMultiply[img1, img0]
which gives:
Regards -- Henrik