Do I have to pick a single format?

No, and the professional approach is precisely not to pick one. HTML's `picture` element lets you define several versions of the same image; the browser selects the most efficient format it supports and quietly skips the ones it does not. That way you take AVIF's speed gain in modern browsers without losing a single visitor in older environments. The obligation to choose a single format only arises in contexts where you cannot use this mechanism, such as an email newsletter.

Which should I use for images requiring transparency?

All three support the alpha channel, so transparency is no longer a criterion that determines the format choice on its own. In the past, if you wanted transparency you were condemned to PNG and therefore to large files; WEBP and AVIF removed that dilemma. In this case the decision is made once again along the axes of efficiency and compatibility. Just watch one thing: when working in lossy mode, check whether degradation has appeared in soft edge transitions, especially with sharp-edged logos.

What should I do with screenshots and text-heavy images?

You need to be careful with this content type, because lossy compression can soften fine text edges and legibility is directly affected. At high quality settings both WEBP and AVIF usually give clean results and the file still stays smaller than the PNG, but batch converting with aggressive settings is risky. For images like these, experiment on a few samples and check the result at one hundred percent zoom. If absolute crispness is mandatory, staying with PNG or considering the lossless modes is the safest route.

PNG, WEBP or AVIF for Site Speed?

Q: Is WEBP obsolete now — should I go straight to AVIF?

WEBP is still a valuable middle rung and it is not obsolete. AVIF generally offers more efficient compression, but WEBP's browser and tooling support has been established for longer and it is recognised by a wider range of software, from content management systems to image editing programs. If you are building a fallback chain, making AVIF the first rung, WEBP the second and PNG or JPG the last is a balanced solution. If you can only offer a single modern format, decide according to the technical profile of your audience.

The question is more complex than it looks

Answers to "which image format should I use for my website?" usually declare a winner. The truth is that this question cannot be answered with a single winner, because the three formats are strong at different points and the web's biggest variable — the visitor's device and browser — is not under your control.

In this article we compare the three formats against real criteria, then explain the practical strategy most sites should adopt.

Brief portraits of the three formats

PNG

It works losslessly: it stores the exact value of every pixel and discards no information. It supports the alpha channel and its support for it is extremely consistent. It opens in every browser, on every device, in every program.

Where it is strong: Sharp-edged graphics, logos, screenshots, images containing fine text, illustrations with few colours. With this content lossless compression works efficiently and the file stays reasonable.

Where it is weak: Photographic content. Natural texture and continuous colour transitions cannot be efficiently encoded by lossless algorithms; the PNG version of a photograph is surprisingly large. On the web that translates directly into a slow page.

WEBP

The first widely adopted generation of modern formats. It can work in both lossy and lossless modes and supports the alpha channel. It is noticeably more efficient than JPG.

Where it is strong: The balance between efficiency and compatibility. Browser support has been established for a long time and a wide range of software, from content management systems to image editing programs, recognises WEBP. That is an advantage not to be underestimated in practice.

Where it is weak: It is not as efficient as AVIF. At the same visual quality it generally produces larger files.

AVIF

A next-generation format based on the intra-frame coding of the AV1 video codec. It supports the alpha channel, HDR, wide colour gamut and high colour depth. It has both lossy and lossless modes.

Where it is strong: Compression efficiency. At similar visual quality it produces noticeably smaller files than JPG — the commonly cited roughly-half figure is a generalisation, but its direction is right — and it is generally more efficient than WEBP too. With photographic content the difference is striking.

Where it is weak: Compatibility. Current mainstream browsers support it, but older devices, older operating systems, many desktop programs and some platforms do not. Encoding is also computationally heavier; producing files takes longer.

Comparison table

| Criterion | PNG | WEBP | AVIF | |---|---|---|---| | Compression efficiency | Low (for photos) | Good | Best | | Lossless mode | Always | Available | Available | | Transparency | Yes | Yes | Yes | | Browser support | Universal | Very wide | Current browsers | | Desktop program support | Universal | Wide | Limited | | Encoding speed | Fast | Fast | Slower |

The critical insight: this is not an either/or question

If you have read this far you will have noticed a tension. AVIF is the most efficient but the riskiest. PNG is the safest but the slowest. Landing in the middle does not look like a solution either.

The solution is not to choose between the formats but to offer all of them at once.

HTML's picture element exists for exactly this job. You define several versions of the same image; the browser selects the most efficient format it supports and quietly skips the ones it does not. The visitor notices nothing — it simply loads faster in a modern browser.

A typical fallback chain is built like this:

AVIF — browsers that support it get the smallest file
WEBP — environments that are modern but do not support AVIF land here
JPG or PNG — the final safety net for the oldest environments

The cost of this approach is having to produce and store several versions of every image. The gain is both speed and reach; you do not sacrifice either one.

But what if you have to pick a single format?

In some contexts you cannot use the picture mechanism — an email newsletter, uploading to certain platforms, sharing a file directly. In that case the decision is made according to content and audience:

Photographic content, current web audience → AVIF or WEBP. WEBP is safer, AVIF is faster.
Photographic content, audience profile unknown → JPG is still the safest universal choice.
Logo, icon, sharp-edged graphic → PNG. Lossless, consistent transparency, opens everywhere, and already small with this content.
Screenshot, dense text → PNG, or a high-quality WEBP. Legibility is the most important criterion.
Transparency required, file must be small → WEBP or AVIF; both support the alpha channel.

A common mistake: sacrificing the source

There is a point often skipped in the format debate. The optimised files you produce for the web are delivery copies, not the master copy.

When you produce a lossy WEBP or AVIF, the discarded data does not come back. If you later need to resize the image, produce it at a different quality setting or convert it to another format, you will need the lossless source.

That is why you should not delete the original PNG when converting PNG to AVIF. Let the source stay lossless; you can regenerate the delivery copy as many times as you like.

What the format cannot solve

One final warning: format optimisation is only one part of the page speed problem and does not solve everything on its own.

If you are serving an image at 4000 pixels wide that appears at 400 pixels on screen, making the format AVIF does not eliminate that waste — it just packages the waste a little more efficiently. Producing images at the size they are actually used at usually delivers a bigger gain than changing format.

In the same way, lazy-loading images below the fold and removing unnecessary images from the page are gains independent of format.

In summary

AVIF is the most efficient, WEBP the most balanced, and PNG the safest and still the right choice for sharp-edged content. But the real answer is not to pick one of them: build a fallback format chain and let the browser choose what is best for itself. Everywhere you can do that, you get speed and reach at the same time. Where you cannot, the content type and your audience profile make the decision — and in every case, do not forget to keep your lossless source.