Heavy images cost you money and traffic. They cost you money because they require both significant storage space and bandwidth. Since your web host will usually give you a limited amount of storage space and a maximum data transfer allowance, heavy graphics can cause you to exceed those limits, in which case you’ll have to pay extra.
Then, heavy images cost you traffic: put up a web page that takes more than 10 seconds to load, and your visitors will run away faster than you can say “back button”. If you happen to be running an e-commerce Web site, you already know that traffic equals money, so heavy graphics will make you lose both.
Fortunately, there is a solution: you can optimize your images for the web. Your images should be in either .gif or .jpg formats (.gif works best for logos and navigation buttons, while .jpg works best for photographs.) The idea is to reduce the size of your graphics so that they take as few bytes as possible while retaining acceptable quality.
Another useful tip is to use thumbnails. Thumbnails are miniature versions of a picture that are hyperlinked to its actual size version. The thumbnail will load fast, and by clicking on it your visitors will be able to see the actual size version.
Also, it is very important to specify the width and the height of your images in your HTML code. Since the text of your page usually loads faster, if you don’t specify the width and the height of your images the browser will have to reposition the text once the pictures load, consuming more time. If you take the time to specify the width and height of your images, the browser will lay out the text where it should go from the beginning, even before it loads the images, saving time.
Use all these techniques and you will have a faster loading Web site, while you will save more of your storage space and data transfer allowance for that useful content your visitors are always looking for.