Some examples of what compression really does to your images...

These are the same images from the previous page, only here they're magnified four times so you can see the noise more easily. Of course no one will probably be looking at your images this closely, but then again, it's still good to know how your images are being changed when Photoshop saves them with different levels of JPEG compression...

 
left - maximum (40K), right - high (32K)


You'll notice that the main difference between the above left and right images are the occurance of subtle "boxes" of color in the "high quality" image (do you see them?) Small instances of "random" noise being generated can also be found -for example, the small speck of noise just left of Anna's upper lip. That seems to come from nowhere!

 
left - maximum (40K), right - medium (24K)


Here the differences are already easy to see. The boxes of color seem more clearly defined and they are starting to affect the contours - for example, the bridge of Anna's nose seems more "broken up" and jaggy. The noise also has the unpleasant effect of creating "textures" in the smooth areas (Anna's skin) where they don't belong.

 
left - maximum (40K), right - low (20K)


This is starting to look like a lousy Salvador Dali painting. If you can't see the difference between them ...hmm...

click here to go back...

[an error occurred while processing this directive]