Count image's colors very fast

[Pedroski55]

@deanhystad: Nice, clear link! Thanks!

Apropo colours on computers: 24-bit colours: 16.7 million (2 to the power of 24)

Nearly all computers and displays over the last five to ten years come standard with support for at least 16-bit color, with newer computers supporting 24-bit and 32-bit color. Is there a different between the different levels of color? The short answer is yes. All three color bit depths use red, blue and green as standard colors, but its the number of color combinations and alpha channel that makes the difference. Whether you are viewing pictures, watching a video, or playing a video game a higher color depth is more visually appealing.

16-bit color
With 16-bit color, also called High color, computers and monitors can display as many as 65,536 colors, which is adequate for most uses. However, graphic intensive video games and higher resolution video can benefit from and use the higher color depths.

24-bit color
Using 24-bit color, also called True color, computers and monitors can display as many as 16,777,216 different color combinations.

32-bit color
Like 24-bit color, 32-bit color supports 16,777,216 colors but has an alpha channel it can create more convincing gradients, shadows, and transparencies. With the alpha channel 32-bit color supports 4,294,967,296 color combinations.

As you increase the support for more colors, more memory is required. However, almost all computers today include video cards with enough memory to support 32-bit colors at most resolutions. Older computer and video cards may only be able to support up to 16-bit color.

Can my eyes tell a difference?
Most users cannot tell much of a difference between 16-bit and 32-bit. However, if you are using a program with gradients, shadows, transparency, or other visual effects that require multiple colors you may notice a difference.