Step 3: Reduce the Number of Colors, Check Out Your Palette
Using CorelPhotoPaint or similar program, you can reduce the number of colors in the image. Use the 'Image->Convert to Paletted' command. I tried this in Paint.net with Posterize, but it resulted in WAY too many colors. The CorelPhotoPaint works well, and I'm sure this can be done in photoshop.
I choose the settings shown in the image. Basically, play with it until you get something you like. I ended up with 30 colors.
Here's the output of the color count:
$ ./count_colors.py 01-flower4-reduced_pixel_count.bmp 02-flower4-reduced_colors.bmp
There are 1827 colors in this image, and 1833 pixels:
There are 30 colors in this image, and 1833 pixels:
So, we reduced the image from 1827 colors to 30 colors! This is a good thing ;-)
Check out your palette for any colors that are too close to one-another. If any are very close, you can keep reducing the color count.