Graphic conversion for any 256x192 into MSX1 graphics (Source code in Blitz Basic).

Create a giant file with all RGB possibilities and their respective Lab values. Read this file at the beginning of the conversion routine and you won't need to convert it to Lab in the main loop.

So far, I didn't check the images on any MSX emulated machine, MSX1 or MSX2.
The converter converts (heh) from RGB to the MSX palette provided. You can use any palette you want (16 colors).
So you can use MSX1 Pal or MSX1 NTSC or MSX2 or your custom palette. I want to make that last thing someday. Pretty easy.

Another test...

Something that always bothered me on the MSX, is that most illustrations don't have contours, due to the color limitations. I decided to try something, I got a MSX1 drawing (Rumy from Gall Force), added contours to it completely ignoring color clashes, and then used my converting routine (no manual editing after it).

The converter works decently in photos, so I'd expect it to be pretty good in a drawing that uses exactly the same MSX colors. The converted image with contours still has flaws, of course, but IMHO it looks great and more visible than the original. Definitely this could be a useful tool for graphic design on the MSX.

Left: original image.
Center: manually retouched image with contours (not possible on MSX1).
Right: image with contours after it passed through the converter (possible on MSX1).

Super! Keep up the good work!

Top left --> Leandro Correia (Blitz Basic Tolerance=0)
Top Right --> Tursi (Dither=NONE)
Botton Center --> Rogerup (Screen 2 with Sprites Contour Trick)

If you re-size the small image you don't need sprites trick just apply the right converter is my humble opinion. That make me think if Leandro decide to include contour with resizing feature would be great for enhancing MSX 1 games.