As I have written here the Jpeg 2000 format is not new, just not used as much as people do not really know about it. Below you can compare what happens to the picture quality of the Jpeg when it is converted and compressed.
Notice that is has until 2000 when the format came out only the scientific community used the Jpeg 2000 format. You can see the difference between the two pictures below which shows the Jpeg and Jpeg 2000 format. Notice how the picture does not compress well around the text on the picture. This is normal will Jpeg and Jpeg 2000 does a much better job at the pictures once saved and compressed. Notice that most browsers view the Jp2 standard as PNG.
This is Jpeg
This is Jpeg 2000