Originally Posted by cinco

I just use tracing paper to make a quick reference sketch of the decal to deal with geometric distortion. Once that's imported and you have the scale correct you can set it and the photograph as background images and do the vector work on top. Once you're done you just drop out the background layers. Inkscape is free and there are lots of tutorials for it out there. I was a complete novice and it only took about a week of evenings to learn the program and draw up a full decal set for my Lygie.