Additional features coming soon for both the Pixelizer tool and upscaling.

I begin in introducing a new feature and different types of filters that will be implemented bit by bit.

Luminance Palette

This feature will create a palette based on the brightness of the image, rather than specific colors. In other words, it generates a palette that represents the different brightness levels in the image, using the visual perception of brightness.
It works somewhat like the human eye.
The formula takes into account that the human eye which is more sensitive to green, less to blue, and little to red, so the RGB components have different weights.
Once the brightness is calculated for each pixel, the function builds a histogram representing the distribution of brightness in the image. 

In addition, this function, combines quantized brightness with other color palettes such as the NES palette, choosing the NES color closest to the original brightness. 
Or perhaps a Game Boy version, and many other functions will come later.

I leave you a screen to show you the result of a transformed screen for Game Boy.