title: iOS Image Processing from JPEG
body: <p>I have a stupid question. I want to load a JPEG file and do some image processing. In the processing, the image file must be in pixel=by-pixel (unsigned char*), or in the format .bmp. I want to know how can I do this? </p>
  
  <p>After processing, I want to save this file as .bmp or .jpg, how can I do it?
  Thanks very much and sorry for my poor English. </p>