I think it was transposed, since the grfcodec would not encode it, saying something like "Error: wrong palette". But maybe it was just in another order? I don't know.. but the palette has to be correct, else the grfcodec won't accept it and make it into a .grf.
Now here's something new: A screenshot to tease you a bit
The local farmer of Funborough Farm has made some trails with his tractor
On a different note, after converting the thing to the proper palette, there were some action colors in it. Don't know if you've already learned about them since you're rather new to openttd grfs.. these are blinking colors of some sorts, and you normally don't want them in your sprite (except you're using them on purpose).
Here is a program that can be run over a sprite to replace action colors with similar looking ones: viewtopic.php?f=26&t=7519
I'll repost the sprites you gave me before, after I've done that..
edit: another thing: there is a certain limitation we have to get along with: the road sprites include the ground (grass, bare ground using some palette swap, or with pavement). Therefore for the combination of road and trails, we have to draw the road first, then the trails. Now if there is a x-crossing of road and trail, there can't be done much. The brown mud will be shown over the road. We can live with that I think, just imagine the heavy vehicles crossing the road there have made it muddy.
However, if we have a T-crossing of road and trail, we can make it better looking, if you adjust the half-tiles of the trails accordingly. Just imagine you lay a half tile of the trails over an orthoganal road piece. It should then look like the trail is nicely splitting off the road. Could you do that?
(I'm not sure if it's understandable what I wrote, so ask if it wasn't clear..)