Computer Vision: Algorithms and Applications, Richard Szeliski, 2022 (Springer) - A widely respected computer vision textbook that introduces image formation and representation as core concepts.
Image Classification (CS231n Course Notes), Fei-Fei Li, Justin Johnson, Serena Yeung, and Michael Ryabko, 2023 - Foundational explanations of digital image representation, including pixel values, color channels (RGB), and data structures, as part of an introductory computer vision course.