Less is often more. The user doesn't recognize a high res graphic from a low res one. If the image is good in the first place, was scanned properly, and reduced to a comfortable size, it will look terrific. JPGs, instead of sending limited colors through the wire, tell the computer's operating system via the browser on the client's end of the wire to use its native color palette to paint the image using this specialized color palette. The compression may be severe or slight depending on how the designer set the compression scheme.
Less compression means lossless compression and a better image.
In any event, working with JPGs often make for smaller, faster and better looking images, particularly photographs. Graphics, on the other hand, that have inherent limited color schemes, can be better served by GIF compression. Here are two identical photos one saved as a GIF with as few as 8 colors, and the other a JPG saved at 50 percent compression. Right click on the files and examine the properties for file size. Working on our Look and Feel We will work on a title bars and buttons.