Color Space Conversion usually transforms the image data between RGB and YCrCb (1 luminance channel and 2 chrominance channels), which is an affine transform. The human eye is less sensitive to color, than brightness, so low order bits are often dropped from the YCrCb representation, saving space.
Encryption protects privacy and ensures security. Advanced Encryption Standard (AES) is a popular encryptions algorithm.   For securing data in transit over networks, protocols like TLS are used on top of TCP/IP, while WiFi uses WPA2/WPA3 for link security.

Compression.    View      

Various techniques for compressing an image.


 How JPEG Image Compression Works

 M-JPEG

 H.264

 Display Stream Compression

 Median Adaptive Predictor