XnView Software

I got a histogram of many peaks about a gray image: dotted line peaks and two thin peaks.
It would be great to find some documentation about the histogram.

Unsuccessful attempts
- Reference Manual http://www.xnview.com/wiki/index.php?ti ... ow=breadth
- Wiki http://www.xnview.com/wiki/index.php?ti ... gram&go=Go

FAIK, there's no description of the histogram available, yet.

The four dotted/dashed lines are 20% sections, i.e. first line is 20%, 40%, ... On the left there is 0% grey/red/green/blue, on the right there is 100% grey/red/green/blue. The solid lines are actual colours of your image and like in any histogram the higher the line the more often this colour is used.

In your case it's just three single grey lines because the image seems to use three specific grey tones, only.