ImageHistogram

ImageHistogram[image] plots a histogram of the pixel levels for each channel in image.

ImageHistogram[image, bspec] uses bin specification bspec.

Examples

Display image histogram:

img = ExampleData[{"TestImage", "Lena"}];
ImageHistogram[img]

With specific bins:

ImageHistogram[img, 64]

Please visit the official Wolfram Language Reference for more details.