Should JPEG encoding take into account gamma? When an image is encoded using JPEG, the RGB pixels are first encoded into YUV, and then the UV channels are downsampled. Before actually doing the DCT and encoding the coefficients, JPEG doesn't gamma correct the Y channel. Is this correct? Shouldn't we determine the DCT coefficients that will most affect our viewed result?
The short answer is "no", for reasons covered in Alvy Ray Smith's memo, Gamma Correction. Gamma is not about nonlinearity in human perception, it's about nonlinearity in display devices (and, I suppose, acquisition devices too).