I have an array of bytes that represents the palette indexes of the pixels of an image, and I'm trying to convert this to an image with ImageSharp, so I can save it later as PNG, but I can't seem to find how, can anyone give me an idea on where to look? The palette is not important, I just need N different colors.
ImageSharp images represent the expanded pixel buffer, not references to color palettes. If you have the original palette use it to create the input buffer of actual pixel data. A byte array as described is not, in real terms a fully decoded image.
Reducing a color set to a maximum amount is a question of quantization. There are methods that allow you to do this as well as encoding options that allow saving images in indexed formats.
