Web Design 101: JPEG and PNG – Why do image formats matter?

When designing a website, the main goal of most owners is to have a website that’s highly functional, navigable and aesthetically pleasing.

With that in mind, the common direction is to use spectacular graphics and images—all in an effort to capture the attention of the reader.

Although this is a desirable direction to take it can easily bog down your website, slowing it until it’s unusable. It’s for this reason that professional web designers are hired; not only can they provide you with beautiful designs but they can also utilize space-saving functionality to speed up the loading times of your website.

One of the most important factors in this regard would be the image format. In order to understand the importance, we must first look into the most common types of image formats used on the internet: the JPEG and the PNG.

Joint Photographic Experts Group (JPEG)

The JPEG—also known as JPG—is named after the organization that created the standard file format. In a gist, this format takes an image and compresses it, allowing it to have a highly reduced file size in exchange for a minor loss in detail.

While other methods can significantly reduce file size, you might end with an incomprehensible image—which you won’t want for your website. Meanwhile, JPEG allows you to compress the file size while ultimately retaining as much detail as possible.

Portable Graphics Format (PNG)

PNG, on the other hand, is the most commonly used format that utilizes a lossless compression method. While it can’t reduce file size to a significant degree, it is one of the best formats that can retain image quality to its fullest.

Which is the better file format?

At a glance, it may seem like PNG is preferable, as it won’t degrade your pictures overall but can still produce a lowered file size. While this may seem logical, the truth is that this is not always the case. PNG images may still have too high an image size to be used for your website—thus causing your website to load much slower than your visitors would patiently wait for.

This however, does not immediately mean that JPEG is your go-to. The true answer to this question is unfortunately, an arbitrary “it depends on the situation”. The best rule of thumb to follow is that PNG is better for graphics that have numerous details, lines and words, while JPEG is better for pictures with lots of colours, gradients and textures.

Why does image format matter?

The image format matters because of its effect on your website, either on the display of the image or the strain on your loading speed. JPEG and PNG in particular, differ greatly on two fronts: compression and detail.

JPEG is much better at compressing files, allowing you to minimise the file size of a detailed picture of a landscape for example. PNG, while similarly effective will only be able to compress it to a certain degree but still result in a picture that’s similar in visual quality to the JPEG version.

PNG, on the other hand can better retain the detail of a graphic that has lots of similar colours but has distinct lines, like that of a textual graphic for example. JPEG, when compressing this will group similar pixels and blur the edges, resulting in a visible graininess. Meanwhile, the PNG will produce a flawless output, still allowing you to read the text on your graphic without trouble.


Utilising certain file formats will affect the overall visual impact of your website. By taking note of the effects of each, you can choose the best images for proper visibility while optimising your overall loading speed.

Are you looking for a web design service in Hertfordshire or UK nationwide that can best handle the images you need? Get in touch with us and have one of our specialists handle your website’s design for you! Contact us on 0800 690 6250, or email enquiries@lemongrassmedia.co.uk.

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