What Are Modern Image Formats? A Guide to AVIF and WebP

You’ve invested in high-quality photography for your online store, but your pages still load slowly. Visitors on mobile devices are leaving before your products even appear, and tools like Google PageSpeed Insights flag your images as a major bottleneck. This common problem often stems from using outdated formats like JPEG and PNG, which are too heavy for the modern web. Modern formats like AVIF and WebP offer a solution by providing superior compression, reducing file sizes for faster loading without sacrificing visual quality.

What Are Modern Image Formats Like AVIF and WebP?

Modern image formats are advanced file types designed for superior compression and quality on the web. The two most prominent formats are WebP and AVIF. Think of them as next-generation versions of JPEG and PNG, built to make websites faster. Their main advantage lies in their compression algorithms, which create significantly smaller files while maintaining crisp, clear visuals.

• WebP: Developed by Google, WebP has become a web standard. It supports both lossy and lossless compression, as well as transparency and animation. According to official documentation from Google, WebP lossless images are 26% smaller than PNGs, and WebP lossy images are 25-34% smaller than comparable JPEGs at the same quality index.
• AVIF: Based on the AV1 video codec, AVIF is even newer and often produces smaller files than WebP for the same visual quality. While its adoption is growing, its main limitation is slightly less browser support compared to the more established WebP.

A common mistake I find is content creators assuming that saving a JPEG at a lower quality setting achieves the same result. It doesn’t. Modern formats use more intelligent compression that preserves detail better at a much lower file size, a crucial difference for both user experience and search engine rankings.

Why Should You Switch from JPEG and PNG?

Switching from older formats directly impacts your website’s performance and your audience’s experience. The primary benefits are tied to speed and efficiency. A faster website keeps users engaged, reduces bounce rates, and is favored by search engines. In practice, what I see most often is a dramatic improvement in Core Web Vitals scores after a site adopts modern formats.

Images makeup on average 50% of a web page’s total weight. Reducing their size is the single most effective way to speed up your site.
— HTTP Archive

The key advantages include:

• Improved Page Load Speed: Smaller image files mean your pages download and render faster. This is critical for retaining visitors, as studies consistently show that even a one-second delay can increase bounce rates. Faster loading is a key component of effective page speed optimization.
• Better User Experience on Mobile: For users on cellular networks, downloading large images can be slow and consume their data plan. Serving lightweight WebP or AVIF files makes your site more accessible and less frustrating for a mobile-first audience.
• Enhanced SEO Performance: Google uses page speed as a ranking factor. By improving your load times with optimized images, you send positive signals to search engines, which can help your visibility in search results.

How Do You Implement Modern Image Formats on Your Site?

Implementing modern image formats does not require you to manually save two versions of every image. Most modern systems use automated solutions that serve the best format based on the user’s browser, providing a fallback for those on older software. This ensures everyone sees the image without compatibility issues.

Your main options are:

• Content Management System (CMS) Plugins: Platforms like WordPress, Drupal, and Joomla have numerous plugins (e.g., Imagify, ShortPixel) that automatically convert your uploaded JPEGs and PNGs into WebP. They also handle the delivery, serving the WebP version to compatible browsers and the original file to others.
• Content Delivery Networks (CDNs): Services like Cloudflare, Cloudinary, or Imgix can automatically optimize your images on the fly. When a user requests an image, the CDN checks their browser’s capabilities and serves the most efficient format, whether it’s AVIF, WebP, or the original JPEG.

Consider this scenario: an e-commerce store specializing in detailed art prints was struggling with slow category pages. Their high-resolution PNG images, averaging 2 MB each, were causing a 12-second load time on mobile. After integrating a CDN with automatic image optimization, the platform began serving compressed AVIF and WebP versions. The result was a 70% reduction in image file weight, cutting the average page load time to under 3 seconds and decreasing their mobile bounce rate by 25% within a month.

Why Compression Still Matters with Modern Formats

Yes, compression remains vital. Converting a large, unoptimized image to WebP or AVIF will result in a smaller file, but it will still be larger than necessary. The best practice is a two-step process: first compress the source image, then convert it to a modern format. This ensures you are starting with the smallest possible base file.

For example, a 5 MB JPEG from a digital camera might convert to a 3 MB WebP file. While that’s an improvement, it’s still far too large for a website. If you first run that 5 MB JPEG through an online image compressor, you might reduce it to 500 KB without any visible quality loss. Converting that 500 KB file to WebP could then bring it down to 350 KB. This two-stage optimization yields the best results for performance. This is especially important when you need to perform bulk image compression for SEO across an entire website.

Making the switch to modern image formats is no longer an optional tweak but a standard practice for high-performing websites. Don’t let heavy, outdated images slow you down. A practical first step is to test one of your most important pages using Google’s PageSpeed Insights tool. Analyze its recommendations, then use an image optimization plugin or a free online converter to see the direct impact on file size and speed.