ImageData

ImageData[image] gives the array of pixel values in an Image object.

ImageData[image, "type"] converts pixel values to the specified type.

Examples

Get pixel data:

img = Image[{{0, 0.5, 1}, {0.3, 0.6, 0.9}}];
ImageData[img]
(* {{0., 0.5, 1.}, {0.3, 0.6, 0.9}} *)

Get byte values:

ImageData[img, "Byte"]

Please visit the official Wolfram Language Reference for more details.