WebP and AVIF are two modern image formats designed to replace JPEG and PNG on the web. They deliver spectacular compression gains — up to 50% reduction in file size compared to JPEG at equivalent visual quality — making them essential for web performance optimization and SEO. For e-commerce stores where images often account for 60 to 80% of total page weight, adopting these formats is one of the most effective performance levers available.
Why Image Format Is a SEO Issue
An average web page today weighs around 2 MB according to HTTP Archive data. Of that total, images account for an average of 50 to 60% of the weight — and on e-commerce pages rich in product photos, that percentage regularly climbs to 70–80%. Image weight directly determines network transfer time and, consequently, the loading time perceived by the user.
Google has incorporated page speed into its ranking algorithm via Core Web Vitals, particularly LCP (Largest Contentful Paint), which measures how quickly the largest visible element loads — most often a product image. Reducing that image's weight from 400 KB to 150 KB can bring the LCP down from 3 seconds to 1.2 seconds, the difference between a "Poor" and a "Good" score according to Google's thresholds.
Beyond pure SEO, lighter images improve the experience for mobile users on limited 4G connections, reduce data consumption for visitors, and lower server bandwidth costs. For stores with thousands of product references, the cumulative gain is substantial.
WebP: The Format Developed by Google
WebP was developed by Google and announced in 2010. It relies on the compression technology of the VP8 video codec for lossy images, and on a lossless variant based on LZ77 and Huffman coding for lossless images. WebP also supports transparency (alpha channel) and animations — two features that JPEG does not support (transparency) or only partially supports (animations via GIF).
WebP's compression gains over JPEG average 25 to 35% at equivalent visual quality, according to Google's studies. In lossless mode, WebP is on average 26% smaller than PNG. These figures vary by image type: photographs with complex content and many details benefit from gains close to the cited averages; illustrations with flat colors and sharp details can see even greater gains in lossless mode.
Browser support for WebP is now universal: Chrome, Firefox, Safari (since 2020), Edge, Opera, and virtually all mobile browsers support WebP. According to caniuse.com, global browser coverage for WebP exceeds 97% in 2026. There is no longer any technical reason to serve JPEG instead of WebP for the vast majority of visitors.
AVIF: The Next-Generation Format
AVIF (AV1 Image File Format) is an image format based on the AV1 video codec, developed by the Alliance for Open Media (which includes Google, Apple, Mozilla, Netflix, Amazon, and others). Specified in 2019 and supported by major browsers since 2021, AVIF represents a significant step forward compared to WebP in terms of compression efficiency.
AVIF's compression gains over JPEG average 40 to 55% — considerably better than WebP's 25–35%. Compared to WebP itself, AVIF is generally 20 to 30% smaller. These gains are particularly pronounced on high-detail photographs and HDR (High Dynamic Range) images. AVIF supports transparency, animations, HDR color profiles, and color depth up to 12 bits.
Browser support for AVIF is growing rapidly: Chrome and Firefox have supported it since 2021, Safari since version 16.4 (2023). In 2026, global coverage exceeds 93%. Its main drawback is its higher decoding complexity, which can slightly slow rendering on very old devices — a trade-off that is generally acceptable given the file size savings.
JPEG vs WebP vs AVIF: Format Comparison
To illustrate the differences between these formats concretely, consider a typical e-commerce product photo: a packshot of a shoe on a white background, 800×800 pixels, at equivalent perceived visual quality.
- JPEG (quality 85): ~180 KB — universal format, no transparency, no animation, lossy compression only
- WebP (quality 80): ~120 KB — 33% savings, transparency supported, animation supported, 97%+ compatibility
- AVIF (quality 60): ~75 KB — 58% savings vs JPEG, 37% vs WebP, HDR supported, 93%+ compatibility
These size differences multiply across an entire store. For a product page loading 6 product images, switching from JPEG to AVIF saves 630 KB per page — nearly half the data to transfer. Over a month with 50,000 product page views, that's 31 GB of bandwidth saved on images alone.
Lossy and Lossless Compression
Both formats support two fundamentally different compression modes. Lossy compression reduces file size by discarding information that the human eye perceives little or not at all. An algorithm analyzes the image and approximates less perceptible areas — typically uniform backgrounds or low-contrast zones. This is the mode used for product photographs: a quality level of 75–85% for WebP or 55–65% for AVIF produces results that are visually indistinguishable from the original file.
Lossless compression preserves every pixel of the original file, but uses more efficient compression algorithms than PNG or TIFF to reduce file size. WebP lossless is on average 26% smaller than PNG at identical quality; AVIF lossless is even more efficient. This mode is suited to screenshots, logos, vector illustrations converted to bitmap, and images where absolute precision is required.
Which Quality Level Should You Choose?
Impact on E-Commerce SEO
Adopting WebP and AVIF improves SEO through several mechanisms. Directly, lighter images reduce LCP — the Core Web Vital metric most impacted by product images. A better LCP improves Google's Page Experience signal, which can favor ranking in organic results, particularly on mobile.
Indirectly, faster pages improve bounce rate and time on site — behavioral signals that Google may use to evaluate page quality. On mobile, where more than 60% of e-commerce searches take place, speed is even more critical: a page that takes 4 seconds to load loses an average of 53% of its mobile visitors before the page even finishes loading (source: Google/Deloitte).
For Google Images — a non-negligible acquisition channel for e-commerce stores — the technical quality of images (resolution, format, dimensions) influences indexation and display in image search results. Images that are properly optimized and served via CDN with stable URLs also improve this channel.
How Lexiik Handles Format Conversion Automatically
Manually converting thousands of product images to WebP or AVIF is a tedious task that most merchants neither have the time nor the tools to carry out. Lexiik fully automates this process through its CDN pipeline.
When a product image is first loaded by a visitor, Lexiik fetches the original file from your PrestaShop server (JPEG, PNG, or any other format), converts it to WebP and AVIF, then stores these optimized versions on Cloudflare R2. From that point on, Lexiik serves the appropriate format based on the visitor's browser: the HTTP Accept header sent by the browser indicates which formats are supported (for example, Chrome sends Accept: image/avif,image/webp,*/*), and Lexiik responds with the best available format.
- The visitor requests a product page; their browser sends an Accept header indicating supported formats
- Lexiik checks whether an optimized version of the image already exists on the CDN
- If not, Lexiik fetches the original image from PrestaShop and converts it to WebP and AVIF
- Lexiik serves the most efficient format supported by the browser: AVIF first, WebP if AVIF is not supported, JPEG as a fallback
- The converted image is cached on Cloudflare R2 with a one-year TTL for all subsequent visits
This process is entirely transparent for both the merchant and the visitor. No template changes are required, no additional compression plugin to install. Lexiik's PrestaShop module handles the entire conversion and delivery pipeline.