I seek to better understand JPEG compression. My camera takes pictures that are on the order of 700KB, but after minimal or no adjustment in Picasa, they save to about 1/3 the original size. Now, I know there’s EXIF information as part of the file, and that’s still there after the resave. I also know that JPEG’s are supposed to degrade with successive saves – however, I can’t detect any degradation of the image. So my questions are thus:
1. Am I loosing quality, or is my camera’s compression algorithm that shitty? I have taken snippets of both the original and the compressed image and blown them up to 800% and I cannot see any difference. At this point I’m seeing the JPEG gradients, not any recognizable part of the image, so I doubt it’s that I’m just not noticing it.
2. If I am not loosing quality, what’s different between the images? Can I reliably resample all my pictures and save my self several gigs of space?
