Here's a picture. The same original scan was used and saved at 30%, 50%, 80% and 100% quality. Since it would be too easy to just look at the link, they are all in one image now.

Can you tell which is which? (I mixed them up)

The 100% file is 69,750k while the 30% file is 14,388k. Roughly 21% smaller file size, while the image displayed is the same size.

If you want bigger pictures on Jackpot, save the more compressed in JPG format.

Someone with a really good, large monitor, tell me which is the 30% and which is the 100%? (if you can)