Web Image Format: JPEG

Images have evolved into many formats over the years, a handfull of which are responsible for displaying every single image you see on websites and also in emails. There has been a lot of work involved in creating some of these standards, the current popular formats are JPG, GIF, and PNG. While a few of you may indeed recognize all three of the formats, some are scratching their heads wondering what a PNG file is… This series of articles will demonstrate the difference between the three, explain why you should use one over the other depending on the situation, and also mention information as to why the PNG format will become more popular very soon. This first article in my Image Format series will start off focusing on the most popular format, the JPEG…

Choosing the right file format for your images is a very important decision on the internet, its all about retaining quality with the smallest possible file size. Small file size results in quicker page loading, and since you have a criticle amount of time to make a first impression on the internet, faster page loading results in fewer people leaving your website. Out of the three popular formats , each is suited to a specific type of image. Matching your image to the correct format should result in a small, pristine, fast-loading graphic.

The JPEG Format

The JPEG “jay-peg” format was developed by the Joint Photographic Experts Group and uses a lossy compression to provide support for 16.7 million possible colors. This allows for the complex blend of hues that occur in photographic images and that is the image type JPG is best suited for.

Each time a JPG image is saved, the image will lose some quality but result in a smaller file size. Lossy compression essentially throws away “extra” information, and depending on what settings you use, the thrown out data may or may not even be visible to the human eye. In practical use, a compression setting of about 60% should result in the perfect balance between quality and filesize, without letting the lossy compression do too much damage. One important point to make is that once you lower the quality of a JPG image and throw away the information, the extra data can NOT be regained. So, feel free to experiment, but always be sure to save your original!

Another feature of JPG files is that they can often be saved as a Progressive JPEG. This type of image presents a low-quality image to the viewer at first, and over several “passes” improves the quality of it. Some graphic editing tools allow you to specify the number of passes before the image downloads completely. This will allow a viewer to see the image sooner than normally but it will seem blurry for a second as the rest of the clarity gets downloaded. This criticle few moments can be all the difference in a better experience for your users since a blurry image is better than nothing at all. And, by the time they realize the image is blurry, it is already clearing up.

Although not needed often for photographs, JPG files lack the ability for animation and transparency and also tend to make text look very low in quality when saved at almost any compression setting. If any of these issues are important to your particular image then the GIF or the PNG would be a much better choice as I will explain in my next articles in the Web Image Format series…

To view the next article in this series, click HERE.

About the author

RJ Ponzio

RJ founded Shore Web Tech LLC in 2011. The mission of Shore Web Tech (SWT) is to help small and medium local businesses take advantage of today's affordable technology solutions. RJ currently holds Google's "AdWords Qualified Individual" certification.


  1. Marc Williams

    Very interesting BUT with all the items we MUST consume to just run our daily lives could we get a paragraph telling us what to do? I am getting tired of trying to make choices, tell me whats best for real estate, i trust you.

  2. RJ Ponzio

    Most often, real estate agents are concerned with photographs of homes. Therefore, the JPEG is the best choice. This article is not required reading for anyone as I do it on my spare time for my own reasons, I only hope those out there who wish to learn something new find this information helpful in one way or another.

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