WebP, AVIF or JPG: how to pick an image format in 2026
Most format advice answers the wrong question. Which format is smallest matters far less than where the picture is going — and the honest answer changes completely between your own website and somebody else’s upload form.
- Updated September 2026
- 8 minute read
- Support data from Can I Use
The question everyone asks, and the one that decides it
Ask which image format is best and you get a straight answer: AVIF. It is smaller than everything else at the same visual quality, and by September 2026 about 95 percent of browsers read it. On that measure the argument is over.
Then you try to upload an AVIF to a university application portal and it is rejected without an explanation, because the form was written to accept JPG and nobody has touched it since. This is the part the comparison articles leave out. The format that wins on compression is frequently the wrong file to send, and the deciding question is not which is smallest but who opens it next.
of browsers read WebP
of browsers read AVIF
AVIF savings over JPG
Answer three questions and the picker below will tell you what to save, and why. The rest of the article explains the reasoning, in case you disagree with it.
Which format should you use?
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What the four formats actually are
Four formats cover essentially everything you will meet. Two are thirty years old and universal; two are modern and better at their job, with a small compatibility tax attached.
The four formats, side by side
checked September 2026| Format | Support | Size vs JPG | Transparency | Best for |
|---|---|---|---|---|
| JPG | Everywhere | The baseline | No | Photographs headed somewhere you do not control |
| PNG | Everywhere | Usually larger for photos | Yes | Screenshots, logos, anything with sharp edges |
| WebP | 96.8% of browsers | 25 to 34% smaller | Yes | Almost everything on a site you own |
| AVIF | 95.4% of browsers | Over 50% smaller | Yes | Photographs on pages you control, with a fallback |
The numbers are worth reading carefully. Google’s figure for WebP is 25 to 34 percent smaller than a comparable JPG at an equivalent quality index, and 26 percent smaller than PNG for lossless images. Google’s guidance for AVIF is more than 50 percent off the JPG. Those are averages across many images: a photograph of a face against a soft background will do far better than a screenshot of a spreadsheet.
Where each one actually wins
AVIF, on pages you control
If you run the website, you can serve AVIF to the browsers that read it and something else to the rest. That is what a picture element does, and it is the only situation where the compression win is free of risk. Photographs benefit most; flat graphics benefit least.
WebP, almost everywhere else on the web
WebP is the pragmatic default. Slightly bigger than AVIF, better supported, carries transparency, and encodes fast enough that bulk conversion is not an afternoon. If you want one modern format and no fallback logic, this is it.
JPG, when you do not control what opens it
Upload forms, older content systems, an email to somebody with an unknown device. JPG is the format nothing rejects, and being accepted is worth more than being small.
PNG, for edges and transparency in forms
Screenshots, diagrams, logos and anything that has to be see-through in a place that will not take WebP. PNG is heavier than everything else here, and it is the only heavyweight worth carrying.
The three mistakes that cause almost all the pain
Sending a modern format into an old form
Government portals, university applications and recruitment systems validate the file extension before they look at anything else. Many still accept only JPG, some accept JPG and PNG, and very few accept WebP. Converting to WebP to get under a size cap and then being rejected for the format is a specific and very common way to lose twenty minutes.
Saving a screenshot as a JPG
JPG compression works by discarding detail the eye is unlikely to miss in a photograph. Text and sharp edges are exactly the detail it is worst at keeping, which is why a JPG screenshot develops a grey smear around every letter. Screenshots want PNG, or WebP if the destination allows it.
Converting a transparent PNG to JPG
JPG has no alpha channel, so the transparency does not survive — it becomes a solid background, usually white or black, and you find out when the logo is sitting in a white box on a coloured page. If a picture needs to be see-through, your options are PNG, WebP or AVIF, and nothing else.
A rule that covers most of it
Photographs to JPG unless you control the page. Anything with text, edges or transparency to PNG unless you control the page. When you do control the page, use WebP, and use AVIF for photographs if you are willing to keep a fallback.
How to convert without making it worse
Order matters more than most people expect, because two of these operations throw information away permanently.
- Resize before you compress. Reducing a 4000 pixel image to the 1200 pixels it will actually be displayed at removes far more weight than any quality slider, and it does it without visible damage.
- Compress once, from the original. Every save of a lossy format throws away a little more. Going JPG to WebP to JPG again compounds the loss. Keep the original and re-export from it.
- Judge quality at the real size. Artefacts you can only see at 400 percent zoom do not matter. Artefacts visible at the size it will be displayed do.
- Check the destination first. Read the form’s instructions before you convert anything. Thirty seconds there saves the whole round trip.
The image resizer handles the first step and the image compressor handles the second, both in the browser, so the original never leaves your device.
Questions about image formats
Is AVIF better than WebP?
For compression, yes — AVIF is typically smaller than WebP at the same visual quality, and Google puts the saving over JPG at more than 50 percent. WebP is better supported, at 96.8 percent of browsers against 95.4 percent, and encodes considerably faster. On a site you control, serve AVIF with a fallback. If you want one format and no fallback logic, use WebP.
Can I upload a WebP file to an application form?
Usually not. Most government, university and recruitment portals accept JPG, sometimes PNG, and reject everything else at the extension check. Convert to whatever the form names, even when it means a larger file.
Does converting to WebP lose quality?
Lossy WebP discards detail like JPG does, so yes, a little. What matters is that you convert once from the original rather than re-saving a file that has already been compressed. Lossless WebP exists too and keeps everything, at a size still around 26 percent below the equivalent PNG.
Which format should I use for a logo?
PNG if it has to be transparent and go anywhere. WebP if it is for your own site. SVG, if you have it, beats all of them for a logo, because it stays sharp at every size and is usually a fraction of the weight — it just is not an option when the source is a photograph.
Why is my PNG so much bigger than the JPG?
Because PNG is lossless: it stores every pixel exactly. That is the right trade for a screenshot with text and the wrong one for a photograph of a garden, where the eye cannot tell the difference and the file is three or four times the size.
What about HEIC, the format my iPhone uses?
HEIC is efficient but poorly supported outside Apple devices, and most upload forms reject it outright. Convert it to JPG before sending it anywhere, which iOS will often do for you if you set the camera to Most Compatible.
In this article
Tools in this article
Figures, and where they came from
Browser support percentages are from Can I Use, checked in September 2026. Size comparisons are Google’s own published figures for WebP and the web.dev guidance for AVIF, both measured at matched quality rather than matched settings.
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