Problems working with 8bpp and 24bpp images

[Cesar]

Another time thanks a lot Cesar, your suggestions are very helpfully It's a great idea to calculate a similar color in the table using the distance between two points, I didn't remember that function . I will try it and I comment the results.

You are always welcome

The results of calculating the distance multiplying each term with itself are the same that calculating it as I did with the absolute value, no?

No I didn't. Consider the example:
The point to approximate: P(100, 100, 100).
Two points to choose betwean: A1(75, 125, 100) and A2(100, 51, 100)

diffSkript(P, A1) = |100 - 75| + |100 - 125| + |100 - 100| = 25 + 25 = 50
diffSkript(P, A2) = |100 - 100| + |100 - 51| + |100 - 100| = 49
diffCesar(P, A1) = (100 - 75)*(100 - 75) + (100 - 125)*(100 - 125) + (100 - 100)*(100 - 100) = 625 + 625 = 1250
diffCesar(P, A2) = (100 - 100)*(100 - 100) + (100 - 51)*(100 - 51) + (100 - 100)*(100 - 100) = 49*49 = 2401

diffSkript(P, A1) = |100 - 75| + |100 - 125| + |100 - 100| = 25 + 25 = 50
diffSkript(P, A2) = |100 - 100| + |100 - 51| + |100 - 100| = 49
diffCesar(P, A1) = (100 - 75)*(100 - 75) + (100 - 125)*(100 - 125) + (100 - 100)*(100 - 100) = 625 + 625 = 1250
diffCesar(P, A2) = (100 - 100)*(100 - 100) + (100 - 51)*(100 - 51) + (100 - 100)*(100 - 100) = 49*49 = 2401

To copy to clipboard, switch view to plain text mode 

As you can see, the results differ. Which one is the best? You choose