Cool idea, with a little work this could be a very useful tool for color seeing folk. The method you use could definitely use tweaking though, Ive seen other sites that do this which produce images that look identical to the original to me (im red/green colorblind), but with this there is a significant difference.
The method is definitely lossy - it should be off but consistently off. i.e. the mapping is not perfect but if two colors look close to each other in our lossy mapping then they'll be close to each other in the perfect version. I'll probably update it soon anyway.