ImageMultiply

ImageMultiply[image, x] multiplies each channel value in image by a factor x.

ImageMultiply[image1, image2] gives an image where each pixel is the product of corresponding pixels.

Examples

Darken an image:

img = ExampleData[{"TestImage", "Lena"}];
ImageMultiply[img, 0.5]

Multiply two images:

mask = DiskMatrix[100];
ImageMultiply[img, Image[mask]]

Please visit the official Wolfram Language Reference for more details.