January 25, 2023

PNG vs. JPEG: The Best Image Format for Web Optimization

When it comes to creating a seamless and engaging user experience on the web, the quality and performance of your images play a significant role. Choosing the proper file format for your pictures can significantly affect how they are displayed and how quickly they load. Optimizing website graphics or image content is essential for getting users and optimizing performance.

Nearly 39% of users leave sites due to poor image loading times. Image optimization is essential to improve website performance; it limits image file size without compromising image quality—thus, less resource use, loading speed, and positively influencing SEO.

In this article, we'll discuss the key differences between PNG and JPEG image formats, factors to consider when choosing between the two formats, and tips for optimizing images for web use.

Overview: Differences Between PNG and JPEG Formats

PNG, which stands for Portable Network Graphics, offers several benefits for image usage. One of its key advantages is its lossless compression technique, meaning that the image's original data is preserved without any loss in quality. This makes PNG an excellent choice for high-quality images or graphics that require transparency. However, PNG files tend to be larger, negatively impacting website performance.

On the other hand, JPEG (Joint Photographic Experts Group) is a popular image format for web images due to its use of lossy compression, resulting in smaller file sizes. This compression technique makes it an excellent choice for situations where storage space is a concern. However, one drawback of JPEG is that it does not support transparency, making it less suitable for graphics that require transparent elements.

From planning to launch day, learn how to make your next redesign project a  success with our Website Redesign Guide.

Factors for Choosing Between PNG and JPEG

When it comes to choosing between PNG and JPEG, there are several factors to consider:

  1. Image quality
  2. File size
  3. Compatibility with different software
  4. Transparency

Choosing between PNG and JPEG requires careful consideration of various factors. The quality of the image plays a significant role in determining the appropriate format. For instance, if you are dealing with high-quality images, such as breathtaking sunsets or intricate portraits, PNG is often the better choice. By preserving all the original data, PNG ensures that every detail is faithfully represented. Conversely, if your images have simpler patterns or solid colors and don't require as much intricate detail, JPEG can offer a more efficient solution.

Another crucial aspect to consider is the file size. As previously mentioned, PNG files are generally larger than JPEG files. If you are working with numerous images or if page load times are a concern, opting for JPEG might be more advantageous. However, if file size is not a significant constraint and you aim to maintain the highest image quality, PNG becomes a compelling option.

When it comes to compatibility with different software and devices, both PNG and JPEG enjoy wide support. However, it is important to note that older software or devices may not always support PNG. Therefore, if you want to ensure that your images are displayed correctly across a broad range of devices, JPEG is the safer choice.

Transparency is another factor that can influence your decision. If your image requires transparent elements, such as overlays or cutouts, PNG is undoubtedly the superior option. With its support for transparency, PNG empowers you to seamlessly integrate your graphics into various backgrounds or designs.

From planning to launch day, learn how to make your next redesign project a  success with our Website Redesign Guide.

What are the size limitations for JPG and PNG images?

Understanding the differences between JPG and PNG image formats is crucial when considering their size limitations. Typically, PNG files have larger sizes as they are not compressed as much. On the other hand, JPG images can be compressed to around 10% of the original size on average, resulting in significant space savings. This means that while PNG images may have larger file sizes, JPG images have the advantage of significantly reducing overall file size.

How to Optimize PNG or JPEG Images for Web

The optimal image size on an online platform like WordPress or HubSpot should be 200 x 200 pixels for fullscreen backgrounds between 1600 x 2500 pixels wide, and for many other images, a max size of 8800 pixels. Pictures on the edges will ensure their loading is accurate for the computer or mobile screen.

Here are some steps to achieve image optimization:

  • Resize the image to the appropriate dimensions for your website or project. Larger images may take longer to load and affect your website's performance.

  • Adjust the image quality as needed. PNG uses lossless compression, meaning it preserves all the original data of an image without losing any quality. However, this can result in larger file sizes. JPEG uses lossy compression, which means that some of the original data is lost during the compression process. Adjusting the image quality can help you find the right balance between image quality and file size.

  • Save the image with the appropriate file name. Use descriptive, keyword-rich file names to help search engines understand the content of your images and improve the chances of them being found in search results.

  • Compress the image to reduce the file size. Several tools and services can help you compress JPEG images, such as TinyJPG or Kraken.io and TinyPNG or PNGGauntlet.for PNG images.
  • Use responsive images to ensure your images are displayed correctly on different devices. Responsive images are designed to adjust to the size and resolution of the device they are being displayed on. This can help improve the user experience and reduce your website's load times.

By following these steps, you can optimize your PNG or JPEG images for the web and improve your site's performance. Remember that specific optimization techniques depend on your project's needs and available resources.

How to optimize images for SEO

Optimizing your images for the web not only improves the user experience but it can also positively impact your website's SEO. Search engines like Google use image file size, alt tags, and file names as ranking factors. By optimizing your images, you can improve your website's page load times, which can lead to higher search engine rankings. Here are a few tips for optimizing your images for SEO:

    1. Use descriptive file names and alt tags that include your target keywords.
    2. Keep file sizes small without compromising image quality.
    3. Use relevant images to your content and add value to the user experience.
    4. Use sitemaps to inform search engines about your images. 

The Takeaway

Image optimization is an important aspect of website design and can greatly impact the user experience and search engine rankings. By understanding the differences between PNG and JPEG formats and considering factors like image quality, file size, compatibility, and transparency, you can make informed decisions about how to use images on your website. However, image optimization is just one aspect of creating a high-performing and user-friendly website.

Website redesign is a complex process that considers various factors like user experience, search engine optimization, and website performance. A well-designed website not only looks good but also provides a great user experience that helps to increase engagement and conversions.

If you're considering a website redesign, download our guide to help you navigate the process and ensure your new website is optimized for users and search engines. Our guide can provide you with the information and tools you need to create a website that is fast, responsive, and easy to use. It can also help you understand the latest design trends, best practices for user experience, and how to optimize your website for search engines.

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Elizaveta Shkurina

Sr Creative Strategist specializing in B2B brand creation, sales enablement, and SaaS demand generation. With 8 years of experience, she excels in driving ROI and revenue-driven KPIs through collaborative innovation.


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