JPG, PNG, WebP, AVIF: Decoding Image Formats for Your Website
If you’ve ever stared at your computer screen wondering whether to save an image as a JPG or a PNG before uploading it to your website, you are not alone.
At Webcetera, this is one of the most common questions we get. You want your website to look stunning, but you also know that Core Web Vitals and site speed are crucial for Google rankings. Choosing the wrong format can lead to "Heavy Page" warnings or, worse, broken images for your customers.
Here is our guide to getting it right every time.
The "Legacy" Formats
These are the files we’ve used for decades. They are the "safe" options because they work on every device, from a 2010 Nokia to the latest iPhone.
1. JPEG (or JPG)
Best for: Photographs. JPEG uses "lossy" compression. It’s brilliant for photos because it can handle millions of colours efficiently. However, it doesn't support transparency (no see-through backgrounds).
2. PNG
Best for: Logos and Graphics with text. PNG is "lossless," meaning it doesn't lose quality when saved. It supports transparency, making it the only choice for a logo that needs to sit on top of a coloured background.
The "Modern" Formats (Next-Gen)
Google prioritises websites that use these formats because they make the web faster and more sustainable.
3. WebP
Best for: The "Safe" Modern Choice. WebP is the current industry standard. It offers much smaller file sizes than JPEG but keeps the quality high. It also supports transparency. In 2026, it is supported by roughly 96% of browsers.
4. AVIF
Best for: Maximum Performance. AVIF is the newest format. It can be up to 50% smaller than a WebP file. If you are obsessed with speed, this is your winner. However, it’s still "new" enough that some older iPhones and corporate computers can't see it yet.
The Platform Trap: Shopify vs. Webflow
How you handle these files depends entirely on which platform your website uses. We specialise in optimised Shopify development and bespoke Webflow design, but look out for how images are handled on your own platform like Wix and Squarespace.
Shopify: The "Set and Forget" Approach
Shopify is the gold standard for image handling. You can upload a high-quality JPEG or PNG, and Shopify’s servers do the hard work for you. It automatically generates WebP and AVIF versions and serves the best one to each visitor. If a visitor is on an old computer, Shopify detects this and serves the original JPEG as a fallback. It’s foolproof.
Webflow: The "Manual" Approach
Webflow gives you more control, but it requires more care. Webflow has a "Convert to WebP/AVIF" tool in the assets panel.
Warning: When you use this tool in Webflow, it replaces your original file. This means if you convert your hero image to AVIF, users on older browsers (who need a JPEG fallback) will see a broken image.
Webcetera Pro Tip: For most Webflow sites, we currently recommend uploading high-quality JPEGs and converting to WebP, as its compatibility is much higher than AVIF. Webflow defaults to AVIF, though, but if you would like to use AVIF for performance, keep a backup of the original JPEG.
The Quick Comparison "Cheat Sheet"
If you just want the headlines, here is your quick reference guide:
