Command-line utility to convert images to 256 color Windows 3.x BMP file format
This tool is primarily intended to convert modern large megapixel images to smaller size BMPs usable in DOS.
The color reduction algorithm is far from optimal or speedy. The bigger the output file size that is requested will exponentially increase the processing time. The scaling of an image is fairly quick. It is only color remapping is that is slow. If you output anything larger than 128x128, expect to wait. When it is creating a 320x200, expect to wait a lot longer. You may even think it has even crashed or hung.
As a general rule, you probably will want to always us the -m switch. Basically, it will to a specific (built in) color palette. Even when I fed it a bunch of photos, they turned out reasonable using that palette. Without that switch, the most popular image colors are used for the palette. Some images will look really good. But most will just look weird.
Maybe someday... Maybe, I'll improve the color reduction process and improve performance. Maybe, I'll work out an additional palette generation method to produce better unmatched images. Maybe, I'll provide Linux and Windows binaries. Maybe, I'll add some other options. Maybe, ....