WebP and AVIF explained: do you need to worry about image formats?
WebP and AVIF are newer image formats that produce meaningfully smaller files than JPEG and PNG at similar visual quality, and both are supported by all current browsers. For most template-based sites, an image optimization tool or build step handles the conversion automatically, so you rarely need to choose a format by hand.
JPEG and PNG have been the default web image formats for so long that most people never think about the choice at all. WebP and, more recently, AVIF exist to do the same job with meaningfully smaller file sizes, and both are now supported by every browser you need to care about. The question worth answering isn't which format is technically better. It's how much of this you actually need to manage yourself.
What changed, in plain terms
JPEG compresses photographic images well but has to trade off quality for file size in a fairly blunt way, and it doesn't support transparency. PNG supports transparency and lossless quality but produces large files, especially for photos rather than simple graphics. WebP and AVIF were built to close that gap: better compression than JPEG at similar visual quality, transparency support like PNG, and file sizes that are routinely 25 to 50 percent smaller than the older formats for the same image.
| Format | Typical file size | Transparency | Browser support |
|---|---|---|---|
| JPEG | Baseline | No | Universal |
| PNG | Larger, especially for photos | Yes | Universal |
| WebP | 25-35% smaller than JPEG, similar quality | Yes | All current browsers |
| AVIF | Often smaller still than WebP | Yes | All current major browsers |
Smaller files matter more than the format name
The actual benefit isn't the format itself, it's what a smaller file does for your page. Images are usually the heaviest part of any page load, and largest contentful paint, one of the metrics search engines and real users both care about, is very often an image. Shrinking that file without a visible quality drop is one of the highest-leverage speed changes available on a typical small business site, ahead of most other technical tweaks.
Do you need to pick a format yourself?
For most people running a template-based site, no. This is one of the areas where tooling has quietly solved the problem for you. Image optimization plugins, build tools, and many modern hosting platforms automatically convert and serve WebP or AVIF to browsers that support them, while falling back to JPEG or PNG for anything that doesn't. You upload a normal image and the delivery layer handles the rest.
The technique behind this, if you're curious, is the HTML picture element, which lets a page offer several format options and let the browser pick the best one it supports. You don't need to write this by hand unless you're editing raw template code yourself. If you are, it's a small, well-documented pattern.
- ›You upload one photo in its original format
- ›Your build tool or host generates AVIF and WebP versions automatically
- ›Each visitor's browser is served whichever format it supports best
- ›You never have to manually convert or choose a file to upload
Modern tooling handles format selection behind the scenes on most template-based setups.
When it's worth handling manually
If you're hand-editing HTML on a static template with no build step or optimization plugin in place, it's worth converting your largest, most important images yourself, particularly hero images and anything above the fold. A free online converter or a tool like Squoosh gets you there in a couple of minutes per image. You don't need to convert every icon and thumbnail on the site. Focus on the handful of large photographic images that actually weigh down the page.
- 1Identify your heaviest imagesHero photos, large background images, and full-width galleries are usually the worst offenders.
- 2Convert to WebP or AVIFA free tool like Squoosh does this in the browser with no install needed.
- 3Compare the visual resultCheck at the actual size it displays on your page, not zoomed in. Most quality loss is invisible at real display size.
- 4Keep a fallback if you're unsure of supportA picture element with a JPEG fallback covers any edge case browser, though this is rarely necessary today.
What doesn't matter here
Browser support is no longer a real concern. Every current version of Chrome, Firefox, Safari and Edge supports both WebP and AVIF, which wasn't true a few years ago when Safari lagged behind. If you're basing a decision on outdated support tables you may have seen, that reasoning is stale. The remaining question is purely about file size and workflow, not compatibility.
- ✓WebP and AVIF produce smaller files than JPEG and PNG at similar visual quality.
- ✓Browser support is no longer a real limitation for either format.
- ✓Most template tooling and hosting platforms convert and serve these formats automatically.
- ✓If you're editing raw HTML with no build step, converting your largest images manually is worth the few minutes it takes.
- ✓The size reduction matters more than which of the two newer formats you pick.