title: What extra information is stored in a photograph taken by a digital camera?
body: <p>When I take pictures with my camera the file sizes seem exceedingly large. In this example the original is 5186kb. I wrote a java program to just read the image and then write it again, removing any information except the pixel values.</p>
  <p>The first time it is rewritten, the file size goes down to 1005kb, over a 500% reduction! To make sure I wasn't losing data to compression I iterated the program 100 times on the resulting images and the file size stayed at exactly 1005kb with no loss in image quality.</p>
  <p>My question is, what is the camera storing in the other 4181kb? Some sort of metadata I know, but it seems like a lot. I would like to know what I am losing by resizing my images like this.</p>