Why recording a still image using a mobile camera is taking up more space? I know basic video compression technique .In that it reduces spatial redundancy and temporal redundancy.If it is so why recorsing still image using camera takes more space.Why compression technique cannot remove temporal redundancy in the still image video.
A still image doesn't have any temporal redundancy to exploit - it is a snapshot of a single point of time! Also, the quantization parameter will be low. Video compression uses higher quantization parameters since each individual frame is seen for a fraction of a second, so in a normal playback mode, the user doesn't get to focus on the details within each frame. Both of these contribute to the lower file sizes for the average image in a video.