ImageAdd

ImageAdd[image,x] adds an amount x to each channel value in image.

ImageAdd[image1,image2] gives an image in which each pixel is the sum of the corresponding pixels in image1 and image2.

ImageAdd[image,expr1,expr2,…] adds all expri to image, where each expri can be either an image, a number, or a color value.

Please visit the official Wolfram Language Reference for more details and examples on core symbols.